I am building a lt1 procharged 383. The way i figured it out im going to have 8.78:1 compression ratio. If i run 10-12 psi boost will i still be able to run 93 pump gas? I thought i was gonna be able to, but according to summit it will be a race gas motor.

 

Heads cam? What power goals. 12psi might be 400hp or might be 800 depending on the combo.

I was around the same compression and was running 18psi on 91 10% ethanol horse ****. It was a tiny setup and was around 600hp. No issues on pump. People are making 800+ on pump.

 

Not sure whether horses urinate in Sunoco 93 in Indiana, but I run it with 14 pounds of boost with no problems at all. Personally, although Summit has good prices, I would never trust them for technical advice. They only care about moving product, nothing else.

 

The few times I have talked to summit they were very helpful, but seemed to still be living in the 60s. They act like you need 8:1 compression to run pump gas with no boost.

Modern fuel injection and tools have come a long way.

Summit, my other parts vendor, and my builder all told me I couldn't do 12:1 on pump gas with my first motor.

 

Unfortunately, Summit's opinion is probably one individuals opinion.

My opinion of 14psi with 8.8:1 compression and some ported advancedinduction ported stock heads will give you around 700hp on 92 octane gas.

Im running around 600-650hp at the flywheel with 7-8psi on 92 octane no problems.

 

I think you'll be fine. I run 14lbs on an 8.0-1 motor with 91 octane...no detonation. Just get it dyno tuned so you'll know for sure.

 

I ran 8psi on 91 octane on my 383 at 9.8ish:1 ran great pulled hard, made 583rwhp with an exhaust leak, also through a TH400

Jay

 

You can do amazing things on pump gas these days. It is all in the tune.

I run about 18lbs-19lbs on my forged 383 using 93oct pump gas. I have a front mount intercooler.

I make just over 600RWHP on a Mustang dyno through a unlocked TH400 and a 9" rear.

 

ya no prob. i made 670 thru an unlocked th400, big stall, S60, with a 385 8.5 14psi with 93 octane.

 

You should be fine. Add some booster if you have six bucks to burn

 

What pistons are in it?

The tune will be important.

Water injection is a big help in making it live.

Rich

 

my trans am made 800 hp on pump gas with 8.8 cpr and 15 psi, no knock