dalunchbox18

just purchased, my questions are:

-did all 1987 vettes have aluminum heads or did they start mid year or what?..mine has the 081 cast iron heads on it

-cant find any sites for identifiying the black to see if this dude bs'ed me, on the side of the block it says 088, and the back says "sgi 5.7lg gm 8 h26 880"

any help would be awesome

jv9999

iTrader: (1)

081 is a 305 head. I thought 880 was a truck block, but I could be wrong. Look on mortec.com. It should have aluminum heads on it.

FormulaL98

Vettes only used cast iron heads in 85 (first year L98) from 86 - 91 they were aluminum. Also, vettes were equipped with a different oil pan than f-bodys

tony_cogliandro

iTrader: (3)

you seem pretty up on the l98. are they an easy swap? i can use my tpi headers, and everything else if the swap is easy.

FormulaL98

They're as easy as putting any other SBC in a third-gen. As for your headers, yes you should be able to use them. However the exhaust system for 350 car uses a larger y-pipe and mid-pipe in the system, you could use the 305 exhaust but it will choke the motor a bit. You will need to come up with a air intake system off of a pre 1990 MAS car. Make sure you have a e-prom for a 350 car also, I have seen people swap a L98 in and use a LB9 prom but performance has suffered (dont know what the difference is between the two e-proms exactly). How complete is the engine you are wanting to swap in??

convas

Yes, all '87 vettes had the aluminium heads (128's), they were introduced in late '86, all '86 vette verts had the alloys and also late '86 coupes, early '86 coupes had the iron heads.

1roc89z28

i have a question. the difference between the l98 in a vette and a camaro is alluminum heads right?

and how much hp is the difference between the iron head to alluminum heads.?

thx

JakeJr

Yes, around mid-86 is when GM went to aluminum heads on the Vette. My early 86 Vette had iron heads and when I rebuilt the engine I went with Edelbrock aluminum heads. They were a straight bolt-on swap.

I believe the camshafts are different between the 'Y' body (Vette) and "F" body cars. That would mean the ECM programming is different too. Of course, accessory mounting brackets, air filter housings, etc., are probably different too.

Since the Vette is GM's flagship, it usually has higher advertised power than the 'F' body cars.

Jake

tony_cogliandro

iTrader: (3)

thank you for your reply. i have a 305 that is in the car and i want to put in a cam and the L98 heads. i have hooker 2055 3 Inch and tpi.
so its out, clean up and run with it.
i also have a 350 im building but this is for the 305.
i understand the need for reprograming, that is a given. i am taking off the tbi and putting on 91 tpi, i got everything including the computer BUT IT WILL NEED new programing.
i was wondering if i should wait for the edelbrock heads to come down or buy the vett L98 ones? how about the bolt pattern? are the center 2 bolts 90% or 72 like my tpi, if you know?
thanks again

1roc89z28

thx. how much hp does it add?

FormulaL98

Honestly guys, the vette head swap isnt really worth enough to offset the effort involved. Ive heard they are only good for about 10 Hp over iron heads, probably due to aluminums better ability to dissipate heat. The combustion chambers have a slightly better design if I remember right but thier biggest edge over iron L98 heads is weight difference. I believe that the cams between L98's were the same F-body or vette, could be wrong though there might be slight differences. What produced the vettes higher HP numbers compared to similar year L98 F-Bodys was the vettes far superoir exhaust manifolds and exhaust system.

As for the bolt pattern between your 305 (tony_cogliandro) and the the TPI set up wish to install they should both be the same bolt pattern if they were produced after 1986. However beware installing L98 heads on a 305. The L98 heads used a larger combustion chamber (64cc) than the 305 (58cc) so without having the heads milled down you will lose to much compression to have any performance gain. I think your best bet would be to go with the Edelbrocks, you will be much happier with the outcome (performance wise), will not have to deal with having machine work done, and will still be about 40 lbs lighter in the end over your iron stock heads. Compared to whats in the aftermarket and even stock iron Vortec heads, L98 heads flow like crap lol but this also true of most stock GEN1 SBC heads.

Dyno Don

iTrader: (7)

The 113 'vette heads do not have the 72 * bolts on the 4 inside holes.
They are the old pattern 45*.

The L98 'vette heads are 58cc but they have no crossover for the EGR.
The combustion chambers are not better, just smaller.

Another difference in the 'vette motor is, they have the fuel lines on the other side.

tony_cogliandro

iTrader: (3)

dyno you are the man. thanks again.