pump gas compression??

What is the highest safe comp. for 93pump gas with alu. heads and bock filled to bottom of pump hole's, for street /strip car, about 2850lbs.

my 427 windsor was 12.75:1 flat top piston...it would run around town...but not raced on it.

Its not quite as simple as just saying a set compression will work with every combo. Depends on you tuning ability, camshaft, convertor, gearing, Ect.

but generally 11.5:1+ is doable..... but 10.5:1 is safe it your looking for something trouble free and forgiving.

Problems you'll run into are variations in pumps gas from season to season, batch to bach, station to station to station. the consistancy on pump gas sucks !!!

res0rli9 wrote:What is the highest safe comp. for 93pump gas with alu. heads and bock filled to bottom of pump hole's, for street /strip car, about 2850lbs.

why in the world would ou fill it ? pump gas ? ???


11.5 with good pump gas 93 not a problem

BOSS 429 wrote:

res0rli9 wrote:What is the highest safe comp. for 93pump gas with alu. heads and bock filled to bottom of pump hole's, for street /strip car, about 2850lbs.

why in the world would ou fill it ? pump gas ? ???


11.5 with good pump gas 93 not a problem

If you are talking about filling the block?...it was that way when I bought it, and im going to use it.
it will have race gas at the track, or mix.
I know the filled block makes the oil hotter but don't know how much more it'll bring water temp up?
and it only be driven a little bit on weekends .

just wondering, thanks

Ive been running 11.9:1 on pump 93 without any issues. I even race it n/a on pump 93. 10.80's at 4300 lbs.

I tend to think 11:1 is safe for pump gas. Here is why, I owned a 1969 Thunderbird with a 429 thunderjet motor (11:1)when I was in high school in the 80s. I was poor and always put the cheapest gas available in it. Never ever had any issues. I could smoke the tires for as long as I wanted by just letting up on accelerator and punching it again. Tire smoke inside the car usually made me stop. Engine was bone stock and I wish I still owned it. Seats rotated sideways to make entering and exiting easier, My 72 Tbird 429 was the same way 87 octane and no issues. Its steering wheel popped up and to the left when the door opened. thought I broke it the first time that happened. I suppose fuel quality has changed since then but 87 is 87 right?