Got a mint condition L98 short-block from an 89' IROC-Z... problem is, though I know it came stock with a 9.3:1 CR, I don't know what cc the stock heads were nor do I know the stock head gasket measurements. The cc of the pistons would be a nice addition if anyone has those, but if not, well I can figure that out given the other numbers. Anyhow, I greatly appreciate the help!

- Penix

 

The heads should be 58cc, as far as the rest I'm not sure.

 

Iron headed L98, which came in fbodys, had 64cc chambers. Aluminum headed L98s had 58cc chambers.

 

I know the heads were cast, so I guess the heads were 64cc... anyone got casting numbers on these heads?

Okay, that's one part out of the way, now how about the head gasket specs?

Thanks again Y'all

- Penix

 

I have this in backup, should be pretty accurate:
350 / L98
Bore - 4.000
Stroke - 3.48
Dome CC - 0.0
Relief CC - 6.0
Head gasket - 0.031
Deck height - 0.015
Chambers - 64.0
Top ring depth - 0.280

EDIT: Actually this isn't the bible, its also says a LT1 has a 3.9" bore and a 3.66" stroke which is bs.

 

I get 9.31:1 CR with 64cc heads, 10cc pistons, a 4.166" x 0.041" gasket, and a 0.015" deck. Any of this sound about right? Cause I'm getting around 9.95:1 with your combo and I know these things only had a 9.3:1 CR.

BTW- That 3.900" Bore / 3.660" Stroke combo you have there is to a new LS1. Probably just a misprint, but then again, it can't be right about the specs to the L98.

Are Y'all sure these didn't use steel shim head gaskets? I'm pretty sure these blocks had a .025" deck and larger than 10cc pistons.

- Penix