gm 502 crate motor 9:1 compression with edelbrock performer heads and Im putting on a intercooled procharger M1sc 7lbs boost blo thru with fast fuel injection setup. the motor was dyno at 490hp aspirated. What do you think I get out of it after procharger and do you think it will go or blow? Need some opinions Thanks

Whats in the bottom end? what about the valves? Head gasket?

7psi seems high?

It'll most likely blow something. 700Hp or so. Reduce the boost to 5#. With 7# of boost and 9:1 CR you will most likely need to run a mix of 93 octane and some race fuel.

the good part is unless it is running really rich, the spark plugs will melt first and maybe only slight peeling on the top of the pistons. make sure it is rick or race fuel.

the alum heads and intercooler will help some on the detonation with 9 to 1 comp. a 502 crate has the good bottom end and square port heads, but the valves are all stainless, you need some inconel ex valves, find the thickest head gaskets, and lower the boost to 5 lbs.

It'll go like hell before it blows if you run pump gas.

9:1 at 7 pounds will equate to about 12.7& 13.3 final compression - to much for pump gas.

Better run race gas or set it back to about 5-6lbs.

Uncle Dave

9 to 1 is not too high as long as the motor is tuned properly. I have 9:1 in my motors with alum heads and fuel injection. 540 ci making 800 hp with 6 lbs boost. Also the procharger has cooler intake temps so it will be fine.

You do need to make some changes to the motor tho if you want it to last. Tear it down and change the piston ring end gaps, get a cam from RM Builder/ Bob Madera and make sure to double check all the clearances. Switch from head bolts to studs and use MLS head gaskets. Do this and it should live for quite a while.

You will always need to run no less than 93 octane fuel.

I have inconnel exhaust valves with oval port heads, the bottom end is stock. There is a blower cam in there but not sure what one. Are the gm rods strong enough for 700hp? If I change the pistons will it last.

the rods are forged and will hold, you can also run 7pounds with no problem on 93. I have done it for years on cast iron heads.

Can you get 93?

93 is NOT available on the West Coast.
You go from 91 to race gas out here.

700HP is the limit for stock rods and a cast crank.

I have an ilmor 710 and have searched every marina from Port Hueneme to San Diego and even 91 is hard to find.

Its not an issue of paying for good fuel, its an issue of availability.

If you were building an injected or NA engine would you build it at 10:1 or 12-13:1?

Lower that compression ratio my friend, run all race gas all the time, or face problems.





UD