87 engine question
Team Owner
Joined: Sep 2001
Posts: 62,137
Likes: 1,727
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Roller camshaft yes, first year for that.
'128 heads are not as great as '113s, but are not terrible. They need some portwork, but should be just fine for about 300hp unported.
'128 heads are not as great as '113s, but are not terrible. They need some portwork, but should be just fine for about 300hp unported.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
heads
I put 113 heads on my 86 with flat top pistons, and it detonated all the time. I put those 87/88 heads on my engine, and it runs so much better. They have 64cc chambers, and are late cast iron clones. The mileage in my car increased to 33 mph highway, and 23 average. and no detonation.
The 113 heads need a dished piston with about 14cc dish to bring them in where the need to be since they are 58cc.
That is if you 0 deck the pistons, and use the .017 squish tin head gasket.
If you leave the factory .025 deck height, and bolt them on flat tops, with a .040 squish head gasket, ping ping ping ping ping ping..................
The 113 heads need a dished piston with about 14cc dish to bring them in where the need to be since they are 58cc.
That is if you 0 deck the pistons, and use the .017 squish tin head gasket.
If you leave the factory .025 deck height, and bolt them on flat tops, with a .040 squish head gasket, ping ping ping ping ping ping..................
Racer
Joined: May 2006
Posts: 293
Likes: 0
The stock 128 heads and the later 113 heads share the same 58 cc combustion chambers. No compression ratio change. To swap from one to the other, the only thing you have to watch is the self, and non self, aligning rocker arms, and their related hardware.
Team Owner
Joined: Jan 2003
Posts: 20,297
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From: Summerland B.C. Canada
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
128 head castings have the same 58cc combustion chamber as the later 113 head D-port castings. If you read the TPIS literature, they claim fairly significant gains from ditching the 128s for the 113 D-port castings.
Aaron
Aaron
