I went to a speedshop today, and told the guy I wanted to know how much a 550 hp motor would cost. He said I sappose you want to drive this on the street, I said yes, and he said it was possible/but its not. He said I would need a 12.5:1 ratio to get it, and pump gas cannot power a motor over 10:1 compression. I know our cars alone have higher compression and run off pump gas. So I was curious how high have you guys got it to?

 

Im running 11.5:1 on my 383 with 93 octane, and I know others on here are running higher than that...

 

its all in the dynamic compression, not static

 

How many cubic inches are you talking about? 350? 400+?

 

Putting mine together now. Its 12.4 static and I plan to run on pump gas. 93+ obviously but on regular pump gas.

 

http://members.uia.net/pkelley2/DynamicCR.htmlThis is a really good response to your question and a calculator to find DCR

 

when i had the h/c installed, i was told the math comes down to almost 13:1. i run 94+ octane. (im not backing this claim up, just relaying, seems high to me too) they used a very thin head gasket set, 5.3 heads

 

Pump gas is a little vague. I can go to certain gas stations in my area an pump in 100 octane gasoline. Cost is $6.00 a gallon. Right along side are pumps for 87, 89 and 91 octane.

 

92/93/94 pump gas, sorry for being so vague.

Checking out that link

 

I run 11.3 static and 8.9 dynamic. Typically 9.0 dynamic is accepted as the limit among most, but depending on squish and quench you could probably waver a little either way.