So after all this tech talk, what was the answer?

I have run many engines on the street and at the track too.
Iron/iron, iron/ali, ali/iron there's lots of variables here...

But when folks ask me these days, I just say 10 to 1...

Its safe and its old school, flat top piston closed chamber head. blah

But when it comes to hemi's its a whole new ballgame!

I got a street 'all iron' hemi from a guy a few years back with 13 to 1 pistons, driving it on pump gas.
Yes the pistons were worn, but it seemed to run ok?.
0.008 thousanths clearance in the bores and smoked when hot etc...

He said it ran good, cos its got a RACE camshaft...
Yep it was huge around 700 lift... coffee

''Bleeds OFF all the compression at low RPM's''!

I heard that a lot over the years and maybe its TRUE???

Last edited by Gtxxjon; 01/15/22 08:13 AM.
Carpe diem, quam minimum credula postero, thanx Horace!

There’s no point trying to fix stuff that ain’t broke,,, 'but if ain’t broke',,, you is not trying hard enough...