so runing 12.5:1 compretion and geting good power is possible on pump gas?
It's possible, but more likely, it'll be something your not going to be to happy with. Like Adam said, it is all in the combo of parts. The things needed to run a high compresion engine on pump gas would be things like;
Big cam
Lots of
overlap
Aluminum heads to disapate heat
If the engine has poor quench, mega reduced timing.
With the above parts, IE; the big cam, that helps bleed of pressure, the cams RPM range is very hhigh and the accoiated parts to use with it are things like,;
A high stall converter, numerically high gear ratio. This is a no brainer in that it will decrease Hwy. driveability. Then add to the mix the other parts that also "Make" the combo.
Big carb, big tube headers, single plane intake. Driveabilty drops some more.
Also, if the car is to heavy for the combo, it'll be a piggish monster off the line and may never actually see it's full potentail in performance. (ET)
In order to balance the engine and car, you'll need a big diet. What equipment will you remove and live without?
Are manual brakes ok? No A/C or defrost/heat OK to live without?
OH, food for thought. The NASCAR Crasftsman Truck series engines are not only limited in total cubes, but also a 9.0-1 comp. ratio.
They make over 700 HP.
Things that make you go "Hummmmmmmmmmmmmmm."