compression ratio ?
Thread Starter
6th Gear Member
Joined: Mar 2004
Posts: 5,867
From: VA
compression ratio ?
ok.........the 306 im lookin at, i can get it in ANY compression ratio i want. i was thinkin 10.5:1......but i was thinkin this morning, and could i go ahead and bump it up to 11:1 since im gonna be n/a, or would that be pushing it for 93 octane and would have to start running higher than pump gas ?? mind you, this is gonna be a daily driver, sometimes seeing action at a strip, but more than likely, itll get tested at lights more than a "tree". thanks
2nd Gear Member
Joined: Jul 2005
Posts: 463
From: Bethlehem
RE: compression ratio ?
not totally sure, but my dads 70 mach1 has the fourbbl clevelavd and the heads have been shaved and it runs well on 93. not the absolute best, but it has a hot cam too. its been frigged with, so thats prob the main thing. id say 93 works.
Pro. B.S. caller outer
Joined: May 2004
Posts: 9,644
From: IL
RE: compression ratio ?
What heads are you going to run and what cam? Aluminum heads can get away with more compression that iron due to better cooling and usually a better combustion chamber. The cam will have alot to due with it also, the more overlap the more compression will be bled off. I have run 11.5 motors on 93 pump gas and never had a problem, but that is at the extreme limit, and the car was not a daily driver. If it were me, I would stay below 11.1 since you say it will be a daily driver, you never know you might get some bad gas or somthing and the .5 point is only worth about 10-15 hp, so it's not a huge loss.
Thread Starter
6th Gear Member
Joined: Mar 2004
Posts: 5,867
From: VA
RE: compression ratio ?
ORIGINAL: JD1969
What heads are you going to run and what cam? Aluminum heads can get away with more compression that iron due to better cooling and usually a better combustion chamber. The cam will have alot to due with it also, the more overlap the more compression will be bled off. I have run 11.5 motors on 93 pump gas and never had a problem, but that is at the extreme limit, and the car was not a daily driver. If it were me, I would stay below 11.1 since you say it will be a daily driver, you never know you might get some bad gas or somthing and the .5 point is only worth about 10-15 hp, so it's not a huge loss.
What heads are you going to run and what cam? Aluminum heads can get away with more compression that iron due to better cooling and usually a better combustion chamber. The cam will have alot to due with it also, the more overlap the more compression will be bled off. I have run 11.5 motors on 93 pump gas and never had a problem, but that is at the extreme limit, and the car was not a daily driver. If it were me, I would stay below 11.1 since you say it will be a daily driver, you never know you might get some bad gas or somthing and the .5 point is only worth about 10-15 hp, so it's not a huge loss.
Thread Starter
6th Gear Member
Joined: Mar 2004
Posts: 5,867
From: VA
RE: compression ratio ?
heres the kit im lookin at. the guy at trickflow ive talked to, said he'll upgrade to stage 2 cam for me and all the associated stuff for $20 extra dollar 
http://store.summitracing.com/defaul...=egnsearch.asp
http://store.summitracing.com/defaul...=egnsearch.asp
