Scenario:

355 putting out 9.32:1 compression ratio with AFR 195's and TRW forged pistons (4 valve relief)

Considering the loss of CR due to the heat dissapation properties of aluminum, will my compression ratio essentially be "too low"?

I can mill the heads, but prefer not too. Would I notice a big power difference between the 10:1 and 9.32:1. I like the idea of running a lot of advance and 87/89 octane, but really need some ideas on where to go from here.

Thanks

James

 

9. whatever isn't bad, lot depends on what you're wanting to do with it, or the intended application.

 

Well, I was afraid it would put my CR to around 8.4:1 because of the aluminum, but the 88 vette's ran 9.5:1 so I didn't think it was that bad. The use is for a daily driven (to work) engine that can hang with some mildly worked on LS1's when it needs to:

Engine is:

355
Complete Lingenfelter Super ram
LT4 hot cam
AFR 195's (intake at 500 lift = 268.1, exhaust at 500 lift = 199.8)
1.6 scorpion rockers

I am looking for 20mpg out of the above combination. If I can get it out of 89 octane, than I am even more happy with the combo.

What do you think?

James

 

Its not going to lower the compression because of the aluminum heads. The only advantage aluminum has over cast besides being easyer to port is the heat dissapation properties of the material. If you were to take a set of heads one aluminum one cast with the same exact size combustion chambers the CR is going to be the same but the aluminum heads will disapate heat better reducing the chance of detonation. Thats why high CR engines work better with aluminum heads, its like your droping compression due to the heat dissapation properties of the heads but your not touching the CR.