wordguy

You guys seem a little more technical than some of the guys at Corvetteforum

92 Formula

iTrader: (2)

Hi,

Glad you're on the board, but before they lock this thread for being non-tech, I do have a tech question:

I bought an '86 Vette Coupe L98 but I haven't seen the engine yet, it's being sent directly to the shop. If I gave you the vin number would that help tell you if it is an iron head or am I lucky to have gotten one with aluminum heads? I have the title of the donor car.

Anyway, welcome to the board.

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1992 Pontiac Firebird Formula (original 305 TBI) The project has begun:
just purchased 1986 Corvette 350 TPI, Dual fan setup, OEM Posi, GM 3.42 gears and JEGS Ultimate Support Cover for 7.5 rear.

1997 Chevrolet Camaro SS # 379 (1 of 371 Black, T-Top, 6-speed)
1973 Chevrolet Camaro RS/Z28
1969 Chevrolet Camaro SS 350

RIP Dale Earnhardt.

wordguy

Unless i'm mistaken all L98 vettes got the aluminum heads.

Acceld Z

I think they started getting aluminum heads in 1986.

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92Z28
89GTA

88 IROC BOB

Hey Wordguy, I steal ideas from corvetteforum so welcome aboard.

Bob

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350 TPI, 700R4(rebuilt), K&N's, MSD 6AL, Headers, Flowmaster, 160* stat, airfoil, MAF screens cut out. 13.88 @ 101.18 mph

92 Formula

iTrader: (2)

I have been told that most '86 coupes had iron heads, while the '86 convertibles had aluminum heads. Still, sometime during the latter part of production the coupes switched over to aluminum heads, too. The question I've got, is how can I tell if the donor Vette I have is late enough...without waiting for it to be delivered to the shop. I'm a little impatient.

drive it

iTrader: (1)

If you can:
Ask them if the valve covers have center bolts or perimeter bolts; center=alum. and perimeter=iron heads.

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86 406

92 Formula

iTrader: (2)

drive it,

I cannot thank you enough for that answer!! I know for sure it is a perimeter bolt valve cover. So, I unfortunatly have iron heads. Do you know if the iron heads have EGR provisions?

Thank you!!

long&low

HA!!

I've got you beat, I don't own an F-Body or a Vette. My TPI is in an 88 fullsize truck.
*** I Love TPI, It looks so cool.

bjankuski

The iron heads still have provisions for EGR. With the iron heads the EGR is still taken from the number eight cylinder exhaust header and routed into the back of the intake manifold. If you have any other questions on the 1986 Vette, drop me a e-mail, I might be able to answer them. I just bought a 1986 coupe with iron heads.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

SMasterson

Oops! I'm gonna confess too!

'89 GMC Pickup, 4040# with driver.
383 .030x3.75 Stroke
SRP 11:1 pistons (flat tops)
SLP 51006 Hydraulic roller, 3 degrees adv. built in
in: .495" 270 218
ex: .502" 276 224
TrickFlow 23 degree aluminum heads w/.039 quench
Accel 74197 intake, SLP runners, Ported plenum, Air foil
Huge K&N filter, 3" SS pipe, in and out of the MAF
30# SVO injectors
3.73 gears with 295/50/15 rear tires

Love this board though and I have owned two thirdgens in the last two years. Project cars I sold off after I was finished.



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SMasterson

drive it

iTrader: (1)

[QUOTE]Originally posted by bjankuski:
[B]The iron heads still have provisions for EGR. With the iron heads the EGR is still taken from the number eight cylinder exhaust header and routed into the back of the intake manifold.


Ditto the above. Also if you plan on changing only the heads- a "quirk" to keep in mind for compression ratios; the iron heads are 64cc chambers vs alum. head 58cc. The difference was made up on the iron heads by using a thin "metal shim" head gasket, instead of a thicker composition head gasket on the alum. Sorry I don't remember the thickness on the two gaskets.


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86 406

92 Formula

iTrader: (2)

Can somebody give me the horsepower/torque figures on the '86 L98, as well as the compression ratio? I assume 9.8? and 220 horsepower and 320 torque?

BC86TPI-Z51

I have the late model 86 Coupe with aluminum heads.The HP rating was rated at 235 HP and torque was 330-340.Not exactly sure.
YES guys, the late coupes got the alloy heads as well as the vertibles.
However, KEEP in mind, the 86 cars recieved a front Y pipe with 2 precats on them versus the 85 style free flow Y pipe.This choked back the engine a few ponies over the 85 set up.

The iron head was rated at 230 HP, and 300-330 ft lbs...not exactly sure of Tq figures again.

A free flowing exhaust, some TPI mods and prom work, youll easily get to 250 HP and 350 Tq figures and possibly a little higher.Higher, the rest is up to you,such as cam changes, head work,TPI mods etc.

The compression ratio was rated at 9.0:1 for iron heads and 9.5:1 for alloys.
it may have been a little higher..most of the ratings have been conservative numbers.

Btw Im a Vette guy who comes here too..
I find myself helping more then asking questions.Seems as if on the forum, if I ask a question, most people dont know the answer.I guess its because I ask questions that are very un common to the cars and I already can do 90% of my own work already.Took time but im getting better.
Lucky for me, a few tech heads that know their stuff allow me to email them anytime and they helped me out many times.




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1986 Vette Coupe,auto, 357 L98 w/alum. heads,40 over,crane cam,3.73 Gears,The usual Mods..
Had an 86 Bird before..want to get another F car again!