Compression Ratio

[srich1207]

hey guys need a little help figuring out my compression ratio i have tried all of the calculators and they all seem to give me a different answer. I am building a 355 small block it is already .030 over so going to have it taken to .040 over to clean it up a little wear. I am going to go with the HE268 Comp Cam with the Edelbrock E-Street Aluminum heads either the 64CC or the 70CC depending on what is needed from yall's response. I have been doing alot of research that for the High Energy 268 Cam you shouldn't run over 9.1-1 compression? I don't have any idea if this is correct or not, if anyone has any experience with this let me know. Also with my components what is my compression going to be with either Flat Top or Dished Pistons. From what I have found with the 64 CC heads the compression should be somewhere around 10.3-1 and with the Dished it should be around 9.4-1. But honestly I don't have a clue. And if those compressions are right what would it be with the 70CC heads. And where do I need to be with the High Energy 268. This is going in a 72 Cheyenne and I just want torque low-mid range as this truck will probably never see 5000 RPM's. Any help guys will be appreciated.

Thanks

[Beat68CST]

With Flat tops you should be at like 9:1, probably less. Definitely not more, that's with a 64cc chamber. That's if the heads haven't been milled and the deck height hasn't be shortened.


You should be fine dude man. Just don't put any domed piston in there.

[bigsnookmaster]

I'd run the flat top piston with the 70cc heads, or dished with the 64cc head. I wouldn't run the 64cc with the flat tops. Alot has to do with the junk gas we now have thank to George W. for. .02

[bigguy69]

[71c10bbsuper]

with the aluminum heads you should be able to run up around 10 to 1 compression!!!