Author |
Topic: Why Exhaust is Big Problem on 75-81 for
HP |
Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-21-1999 01:27 PM
I wish I could get all of you at
least 300 HP for Christmas for your Corvettes or Chevys. Since I
can't afford that, this will have to do.
Maybe these 2
examples will explain best why exhaust is big problem to making HP
on 75-81.
Example 1 Chevy 350 stock single exhaust w/
cat Backpressure 16.5 psi...........152 hp Remove cat, &
replace stock muffler w/ Cyclone sonic turbo Backpressure 3.5
psi.............210 hp Duals & 2 Cyclone sonic turbos
Backpressure -1/2psi............224 HP That is
+45% Headers not tested.
Example 2 Camaro 350 81 Z28
stock ex.............214
hp Headers..............................228 hp Replace cat w/
hi flo cat........241 HP That is over +12% Not tested w/
duals, expect another 15, which would be 256 HP. That would put
total about +20%
Gas milage goes up too.
Expect you know on a Corvette like
yours duals run straight back from manifolds or headers. The iron
manifolds are not that bad on stock engines especially if you have
to run cats. The more hp one has the more headers help.
Now, one can keep the stock carb & cam this to over 300HP
easy, even 340 or more if everything else is right!
Merry Christmas
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-21-1999).]
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Jack78 Senior Member
   
Posts: 1182 From: Burke, Virginia USA now temporarily located
in Pensacola, FL, Registered: Sep 1999 |
posted
12-21-1999 01:33 PM
Ganey - I live in an area where
pollution testing is pretty strict - I could never get away with
removing my cat converter or changing from the "Y" pipes to duals.
If I go with a better flowing cat (I still have the original) do I
gain much? How about if I change mufflers to something with less
back pressure? Do headers or different exhaust manifolds make much
difference if I have to keep the cat and single exhaust? Thanks.
Jack
------------------ Jack Burke, VA '78 Coupe L-48 bone
stock My first - ever
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andy82 Senior Member
 
Posts: 382 From: Fremont,CA'82
350,AUTO,PS,ACTwo-Tone Registered: May 99 |
posted
12-21-1999 01:40 PM
Ganey,
you exclude the 82's in you posting, is this because they have
stock headers? Does anybody know how these headers compare to
aftermarket ones?
------------------ Andy Fremont, Northern
California Two tone '82, Hypertech Stage II chip Edelbrock
cam, K&N air, high flow exaust, Monza style mufflers. Click
here for my Vette on the WEB
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-21-1999 02:02 PM
Jack
Best Headers & 3" Converters to 2 1/2 duals. I would try
to run headers or manifolds, duals, 2 hi flow cat. converters,
crossover pipe, Dynomax mufflers.
If not possible, hi flow cat & try no mufflers or Dynomax.
Your ex. manifolds are some of the best available so changing
manifolds or to headers is not cost effective.
Cat & single ex. quiets, remove mufflers, too loud for you,
then add even short glasspacks or turbo mufflers. Test- Remove cat
& use test pipe to see diff., then you will know what you want.
See I will never buy a muffler thread in Aftermarket.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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SuperFast80 Senior Member
    
Posts: 3021 From: Toronto, CANADA - Frost Beige
1980 Registered: Aug 1999 |
posted
12-21-1999 02:44 PM
Ganey,
When you talk about 214hp for '81 Z28, where do you get that
from? Wasn't the rating 180-190hp?
The headers give another 15hp, so shouldn't it go to 256 instead
of 246?
Thanks buddy
------------------ 1980 355/300hp USS Corvetteforum SSB
Gold Crew Damage Control Off. Ltjg
*Corvette: The
Only Sports Car That Matters*
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-21-1999 03:20 PM
Andy82
Headers help mainly at higher rpms. The 82 will not turn high
rpms w/ stock Cross Fire manifold so headers would not be cost
effective & would expect 0 to minimal gain. Would expect the
other exhaust mods to help 82 some.
Monty is 82 expert & says the fuel system is capable of 300
HP, but not the manifold. I posted on 12-2-99 on Cross Fire Mods
- Update about using 2 4bl manifold if 300 HP is enough & cam
for it. There is also a Holley 670cfm injector & manifold.
If you want to run gears or higher stall converter, try this cam
TPIS 700-134 221/230 .454/.454 112 LS.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-21-1999).]
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redvetracr Senior Member
  
Posts: 637 From: WI Registered: Aug 1999 |
posted
12-21-1999 03:39 PM
All this talk of headers i have a
new set of headman`s WHY CAN`T I SELL THEM HERE !!!!
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-21-1999 03:51 PM
SuperFast80
Yes, I think the 81 Z28 was less hp. These figures are engine on
dyno complete exhaust, no accessory. Expect you know different dynos
will show different figures, so the exact figures are not as
important as what the changes show. If someone has not seen this
type of info. before, it is enlightening, don't you think? Yes,
you are correct, have fixed to 256.
Redvetracer Put a description of headers here. I don't think
many look in Parts Sale/Wanted section.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-21-1999).]
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fauxrs Senior Member
   
Posts: 1113 From: San Diego 1978 L-82 A31-PW C60-AC
FE7-GYMKANA M21-CLOSE RATIO 4 SPD QBS-255/60-15SBR U81-REAR SPEAKERS
ZX2-CONVENIENCE GROUP Registered: Nov 1999 |
posted
12-21-1999 04:08 PM
Try this.....
Use your rams horn manifolds or factory "Shorty style" headers
from c4. from the manifolds run a 2 1/2" mandrel bent y-pipe (will
require fabrication) merge the two legs of the 'y' into a Flowmaster
merge pipe. this pipe has a smooth transition from 2- 2 1/2" to 1 -
3" - connect to 3" high flow cat - use another flowmaster 'y' and
use 2 1/2" pipes to low backpressure mufflers.
This should be the equal of a dual 2" system. The only difference
being the resistance of one cat vs. two. Should be very close though
as (1) 3" pipe has greater x-sectional area than (2) 2" pipes.
All this and its smog legal too!
This is what I plan to do when I get round to the
engine/exhaust/driveline work.
redvetracer-----send info on headers - i may be interested.
------------------ White 1978 L-82 4-Speed Soon to be
burgundy
Zr-1 glass bumper
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74vette69 Senior Member
  
Posts: 587 From: Oklahoma Registered: Nov 1999 |
posted
12-21-1999 04:32 PM
Put a straw in youre mouth and
blow.Now pinch the center of the straw with youre fingers and
walla!You have just installed a catalytic converter! If what goes up
must come down,then on a motor it is ,what gets in must come out
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andy82 Senior Member
 
Posts: 382 From: Fremont,CA'82
350,AUTO,PS,ACTwo-Tone Registered: May 99 |
posted
12-21-1999 04:58 PM
Ganey,
what I meant the the '82 seems to me the only shark that has
stock headers installed from factory. Don't know if they are good
but maybe that is one reason the '82 is measured 200hp instead of
lees hp in the previous years. And BTW, you are right, the other
exaust mods helped alot!
------------------ Andy Fremont, Northern
California Two tone '82, Hypertech Stage II chip Edelbrock
cam, K&N air, high flow exaust, Monza style mufflers. Click
here for my Vette on the WEB
[This message has been edited by andy82 (edited 12-21-1999).]
[This message has been edited by andy82 (edited
12-21-1999).]
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redvetracr Senior Member
  
Posts: 637 From: WI Registered: Aug 1999 |
posted
12-21-1999 05:03 PM
NEW NEVER BOLTED TO ENGINE Hedman
under chassis hedders 63-82 small block race style (uses
reversion plates)has adjustable collector length,1 3/4"ID tubes
Quality piece $490./Jegs(Hedman#65330)will take $290.+UPS
[This message has been edited by redvetracr (edited
12-21-1999).]
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SuperFast80 Senior Member
    
Posts: 3021 From: Toronto, CANADA - Frost Beige
1980 Registered: Aug 1999 |
posted
12-21-1999 05:13 PM
74vette69, well put.
Ganey, you are damn right! The difference one can make with
exhaust upgrades on these so-called 'smog motors' is incredible.
BTW, I have been kicking around this theory for a while now. See
if you can follow and then comment:
If we look at the '71 hp ratings (the only ones that showed both
net and gross) we see 330 gross for the LT1 and 255 net. I know it
is not an exact science but the conversion rate seems to be
approximately 1:0.77. So lets accept a rounder 20% power loss with
net.
Using that, lets convert the net hp ratings of the L48s from
1975-1980 to approximate gross as well as add 20% for true duals and
no cats (so as to even the score with the 68-74s):
Year Net Appr. Gross True duals gr. 1975 165 206 247 1976
180 225 270 1977 180 225 270 1978 185 231 277 1979 195 244
292 1980 190 238 287
Now if you look at the base hp for 1968 through 1971 (gross
numbers), you will see base numbers from 270 to 300. If we take
these numbers at face value, the L48 is as good as any base engine
offered previously and does not deserve the bad rap.
After all, it was the smog laws that put on more accessories but
the engine didn't change (yes, I knoe compression dropped but that
didn't do much).
What do you think?
------------------ 1980 355/300hp USS Corvetteforum SSB
Gold Crew Damage Control Off. Ltjg
*Corvette: The
Only Sports Car That Matters*
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-21-1999 06:02 PM
Andy
Previous years 75-80 have ratings for L82 from 205 to 230
HP. Highest net is 255 HP @ 5600 72 350 no cat. w/ duals.
Highest small block gross is 375 @ 6200 327.
I have no exp. w/ 82, don't have size info. on your ex., do not
expect your ex. is better than the rams horn manifolds.
Consider this I beat new GTOs, etc. repeatedly w/ 57 Chevys w/
283, 307, 302, w/ 30-30 solid lifter cam, dual ex., rams horn
manifolds like Corvette has. Stock 57 carbs, aftermarket air filter,
supertuned. Stock gears about 3.36. Used 4.56 Posi on the fast
cars.
Why not tell what you did & results for 82 guys?
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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andy82 Senior Member
 
Posts: 382 From: Fremont,CA'82
350,AUTO,PS,ACTwo-Tone Registered: May 99 |
posted
12-21-1999 07:00 PM
Ganey,
quote "Highest net is 255 HP @ 5600 72 350 no cat. w/ duals."
There you have it: true dual exaust w/o cat and headers seems to
be the ultimate solution. Note: HP Numbers also dropped significant
with intro of smog legal equippment.
I for my part have to be smog legal, but noticed a difference by
just changing to high flow cat and tips instead of rear
mufflers. I'd love to see dyno results although I can't compete
to many other folks here in the forum but just for the heck of
it...
------------------ Andy Fremont, Northern
California Two tone '82, Hypertech Stage II chip Edelbrock
cam, K&N air, high flow exaust, Monza style mufflers. Click
here for my Vette on the WEB
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-21-1999 07:03 PM
SuperFast80
Based on more info., a long time ago figured for engines rated
net about 200-325 HP one could take net & add 30%. Now you
want to add for duals, I think your 20% dyno may be optimistic. See
Ex. 2 the 20% included headers. 15% may be a lot to add. If
one adds 30% then adds 15% the total is about the same as you have.
So different methods about same total results!
PS I have been
running way behind on this thread because it takes so long to key in
answers.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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fauxrs Senior Member
   
Posts: 1113 From: San Diego 1978 L-82 A31-PW C60-AC
FE7-GYMKANA M21-CLOSE RATIO 4 SPD QBS-255/60-15SBR U81-REAR SPEAKERS
ZX2-CONVENIENCE GROUP Registered: Nov 1999 |
posted
12-21-1999 08:37 PM
redvetracr:
much more header than I need unfortunatly. 
------------------ White 1978 L-82 4-Speed Soon to be
burgundy
Zr-1 glass bumper
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JK78SA Senior Member
 
Posts: 190 From: Waukesha WI Registered: Oct 1999 |
posted
12-22-1999 02:40 AM
Ganey, Excellent thread you
started. Thanks. I've got a '78 L48 w/ stock exhaust sytem w/ Walker
Super Turbo mufflers. The quietness has been driving me nuts for the
last 3 years, so removed the mufflers & went to the local
muffler shop & had them make me some replacement pipes for
$30.00. Car sounds alot better & I noticed a slight improvement
in lower end torque. However, I would like to lose the cat. But the
guy at the muffler shop highly suggested I not run w/o a cat. They
are really cracking down on emmissions enforcement in my area. He
had heard recently that 2 vette owners that live in the same county
as I do got pulled over. The cops checked out there cars (no cat)
& both got fined $5000.00. One guy had to get an attorney to
keep from having his registration yanked. So I guess I'll have to
keep legal & continue to contribute to the acid rain problem
(create more sulferic acid). What kind or brand of high flow
convertor would you recommend for my application & how much HP
would I end up with? Thanks for your help & expertise. John
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chevyman Senior Member
 
Posts: 155 From: Meriden, Connecticut Registered: Dec
1999 |
posted
12-22-1999 05:49 AM
I also have a 75 and replaced my
exhaust with a dynomax system. The only thing with the cat is I
replaced it with a newer monolythic style and gutted it out. IT
still passes emmision and satifies the emission cops. Sounds
awesome. Maybe you can do the same.
------------------ Eddie Hernandez 1975 Corvette
Coupe Meriden, CT
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-22-1999 10:13 AM
John
Thanks. http://www.randomtechnology.com/
is supposed to be the best. Suggest asking them, they have e-mail at
site.
I think you would be much better off to run duals & 2.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-22-1999).]
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Pacha Senior Member

Posts: 60 From: Buenos Aires, Argentina Registered: Dec
1999 |
posted
12-22-1999 11:43 AM
Would a "shorty" style header and
´69 side exhaust be a good performer combo? It will give you a 2
1/2 dual side exhaust and the posibility to use repro fiberglass
covers so you don´t get burnt as with hooker side pipes.
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fastguy unregistered |
posted
12-22-1999 12:06 PM
This has been a great thread. In
every vehicle I have upgraded exhaust on, I have seen an
improvement. I went from the cheesy manifolds and Y-pipe with single
muffler tiny tailpipe on my 67 350 Camaro to cheap Summit headers
($75) and 2 1/2 dual exhaust with sonic turbos. HUGE difference. I
am going to get another set of Summit headers for the Vette with 2
1/2 duals. I probably won't use a converter set since no one checks
cars that old, especially a car that has antique plates. On my other
cars, I will admit that I have converter "shells". Its basically a
hollowed converter. One car even had a fake converter bottom welded
onto a straight section of pipe! Don't try this at home.
------------------ George DiGregorio 75 Stingray L48
SuperT-10 Milford, MA
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Demar Senior Member
 
Posts: 489 From: Terre Haute, IN USA Registered: Apr
99 |
posted
12-22-1999 12:09 PM
I've eliminated the cat converter
and am running straight dual chambered exhaust. Would this be
equivilent to the dual turbo cyclones?
------------------ Demar 76 L-48
http://www.angelfire.com/in2/demar/index.html Terre Haute,
Indiana
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-22-1999 12:33 PM
Pacha
I don't run that type because I want 4into1 full length headers
for max. power & rpms, the headers point straight back & the
pipes go straight through the crossmember & straight back making
gentle curves around the spare. There is also a crossover pipe.
This is ideal. There are about 2 ways to improve this. One is to
remove spare & avoid the gentle curves. The other can not
disclosed since it needs to be sold to an exhaust co.
I think to run the side pipes you must really like them. All the
turns does not help. One should run a crossover pipe w/ it. Expect
the shorty headers to be a little better than the rams horn
manifolds. Still, it will work & a lot of guys like them. If you
did a topic on this probably the side pipe guys would say do it, ask
about pros & cons. Anyway I am not trying to talk you out of it.
At least you don't have to worry about cats, however those sharp
turns are probably as bad.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-22-1999 01:11 PM
Demar
Having the muffler at the end is ideal. Total ex. system loss
w/ above system w/ headers & turbo mufflers can be less than 15!

------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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JADEE Senior Member
 
Posts: 168 From: MAXVILLE, FLORIDA USA Registered: Oct
1999 |
posted
12-22-1999 01:46 PM
GANEY Would this formula also
work on my 79 Camaro 350 cu. bored 30 over. If so what would be the
h\p if my duals run straight back to mufflers which are 84 turbo
type mufflers. I don't have any other specs. except it's using a
QJET. THANKS AND MERRY XMAS AND HAPPY HOLIDAYS AROUND YOUR HOUSE.
JERRY 79 CAMARO 76 VETTE L-82 SOME MODS
------------------
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-22-1999 03:25 PM
Jerry
I have had a Firebird 400 Conv. & a Trans Am similar to your
Camaro, however it has been years. Expect you know you have the
large live axle in the way that you will have to loop over to be
legal. Basically you want to make as straight as possible, gentle
curves as possible for any car. Anyway will not match Vette system.
One way to deal with the live axle cars is to run pipe straight
back, add mufflers & forget the tailpipes over axle. I barely
attached the mufflers to pipes & suspended the mufflers front
& rear so that a hard jab on the throttle would blow the
mufflers off & leave suspended out of the way. This is
especially good if one does not have headers. This should be done
after staging. Too late now, Gotcha!
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-22-1999).]
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DaveL82 Senior Member
 
Posts: 377 From: Plano TX Registered: Jul 1999 |
posted
12-22-1999 03:41 PM
I used to see vette rams horn
manifolds advertised in Circle Track magazine a few years ago that
were ported. These were for classes that required stock type
manifolds but haven't see them lately.
I have an 80 model vette which runs the exhuast under the
transmission crossmember. This makes it real easy to swap from stock
type exhaust to the so called off highway duals in about an hour. I
can change back quickly if needed.
I have a ZZ4 motor thats runs great but not sure it the stock
manifolds are much of a restriction. Hedman has headers that are
supposed to be emissions legal (should come with the required
certification) for C3's vettes.
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-22-1999 07:16 PM
fastguy
On your Vette the Dynomax Cyclone headers flow great & fit
great!
I am glad you like this topic, anybody else?
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-22-1999).]
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JADEE Senior Member
 
Posts: 168 From: MAXVILLE, FLORIDA USA Registered: Oct
1999 |
posted
12-23-1999 03:51 AM
GANEY EXCELLENT TOPIC AND A
WEALTH OF INFORMATION JERRY
------------------
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Ken73 Senior Member
  
Posts: 840 From: Houston, TX Registered: Aug 2000 |
posted
12-23-1999 11:12 AM
I'll say this much; Ganey's
claims of better performance with better exhaust is VERY valid! I
had the original mufflers on my '82 that finally rotted out - and
just with very low restriction (i.e. rusted out) stock mufflers, I
had tons of "power" (at least I sure felt it) and once I had the new
mufflers put on, I noticed a SEVERE drop in power. (Stock
replacement mufflers.) I'll be investing in better exhaust at a
later date, but I can assure you the '82 suffers from highly
restrictive exhaust as well. The catalytic converter is somewhat
restrictive too, even though it is one of GM's "high-flow" units. I
think the idea of doing a higher-flowing Y-pipe and one of the
RandomTechnology cats is a great idea for the '82, along with some
higher flowing mufflers.
Ken
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74vette69 Senior Member
  
Posts: 587 From: Oklahoma Registered: Nov 1999 |
posted
12-23-1999 11:12 AM
Ganey that loose muffler idea is
pretty sneaky!  I
read in July 99 Car Craft about a 1980 corvette sleeper running in
the nines with cast iron manifolds.He used motorized butterflies
with his exhaust to divert from from 1/78 mufflers to Borla
XR-1s.The car has stock interior,Eagle GTs recapped into cheater
slicks,Q-jet,and 300hp nitrous.
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Monty Senior Member
    
Posts: 2949 From: Park Ridge, IL Registered: Feb
1999 |
posted
12-23-1999 11:23 AM
When I had the crossfire motor
still in my car I had full 1 5/8" headers, no cat and true dual
exhuast with flowmaster mufflers. In my opinion, the improvement
over stock is negligible, especially considering the cost and time
involved switching over. This was also in conjunction with an
aftermarket cam, 1.6" full rollers, K&N's, ignition upgrades.
The problem is that the intake manifold's intake port, where it
meets the head, is about the same size, maybe even smaller in some
areas as the stock, stainless steel headers. The stock headers can
be improved somewhat with a little grinding work. The welds where
the individual tubes are welded to the flange are sloppy, blocking
at least a full 1/4" of the tubes. With a die grinder, this weld can
be grinded flush, the air tubescan be grinded flush on the inside,
and some general port matching will improve flow. The stock cat, as
long as it isn't plugged or melted will flow plenty for the
crossfire.
If I were just starting to mod a crossfire, the first thing I'd
do is open up the intake manifold to match the heads, at least as
much as is possible with out going through the bottom of the
manifold. Comp Cams makes a .450" cam for the L83, this along with
porting will produce the biggest improvement, in my opinion, without
pissing the ecm off.
------------------
1982 White 383 DFI SuperRam Park
Ridge, IL 11.895/120.121mph 438HP/478TQ
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-23-1999 12:00 PM
Monty, Ken73, & Andy82
Thanks for adding your 82 experiences. What is dia. &
length of 82 stock header pipes? I was thinking about the intake
problem & guessed the dual 4 manifold would work good. Have
you seen this from Brandon vette84? http://www.flash.net/~famviz/monster
He posted in Aftermarket, CrossFire/Carb Conversion, maybe he
will tell more of his exp. Sounds like he did not cam it.
74Vette69
Familiar w/ that Vette, besides Q-J, etc. it is running auto
& 3.08, can build.
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
[This message has been edited by Ganey (edited
12-23-1999).]
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Senseiearl unregistered |
posted
12-23-1999 04:19 PM
fauxrs-They're many suitable
headers for this car. Pricing on the same header from different
companies can vary by $200. As an example, I just order Heddman
Headers 68301, smog legal from Summit racing for $234.99. Jegs was
$25 higher and one company wanted $400.
Dynomax is good too. The reason I didn't go with them is that
they don't make a California smog legal header for my 78.
------------------ http://www.orderofthedragon.com/
91 green convertible Flowmasters Power Chip K & N
Filter 1978 Pace Car Eldelbrock manifold, cam &
timing chain, Magnum Roller Rocker Arms, modified exhaust 300+
HP Sensei Earl Bakersfield, Ca.
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
12-26-1999 05:51 PM
One thing that was mentioned
without an example was that the more HP you have, the more headers
help. At the 300 hp level with iron manifolds, headers will increase
to about 350 HP.
Sensei Earl
Nice to see ya over 300!
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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Monty Senior Member
    
Posts: 2949 From: Park Ridge, IL Registered: Feb
1999 |
posted
12-27-1999 03:22 PM
Ganey,
The 82 stainless steel headers have a diameter ranging from 1
1/4" to about 1 1/2". The primary's are narrowed at the 90 degree
bend a little, and the sloppy welding narrows it quite alot, but
that can be corrected with some grinding. The length is comparible
to a set of shorties, about 1-2" above the oil pan flange.
------------------
1982 White 383 DFI SuperRam Park
Ridge, IL 11.895/120.121mph 438HP/478TQ
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Ganey Senior Member
    
Posts: 3792 From: Texas CORVETTE 77 385 C.I. Registered:
Apr 1999 |
posted
01-06-2000 08:19 PM
Monty
Thanks. They say better late than never!
------------------ Cheers Ganey
CORVETTE 77 385CI 6.3L Hi-Perf. Sus. http://ganeys.home.sprynet.com/
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fauxrs Senior Member
   
Posts: 1113 From: San Diego 1978 L-82 A31-PW C60-AC
FE7-GYMKANA M21-CLOSE RATIO 4 SPD QBS-255/60-15SBR U81-REAR SPEAKERS
ZX2-CONVENIENCE GROUP Registered: Nov 1999 |
posted
01-07-2000 10:24 AM
Thanks Sensei..
I'm still planning my exhaust and engine mods for after the paint
which starts this weekend (prep, body work & prime) once the
paint is on then I will start engine/exhaust mods.
I'm writing everything down that i learn here on the forum and
including it in my specs for my upgrades. I have set engine specs
down (even posted them on my web site) but I think they will be
changing for a stroked 350 (3.835" stroke - approx. 396 cu in)
torque monster instead of the more revvy 355 i was planning.
engine specs can be found at http://www.geocities.com/MotorCity/Downs/3057/enginespecs.html
------------------ White 1978 L-82 4-Speed Soon to be
burgundy
Zr-1 glass bumper
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