View Full Version : serious question

03-21-2010, 01:27 AM
most of you guys on here think I'm kind of a jerk off, but I've got a real question this time. I've got a built 4r70w with an aftermarket valve body a trans brake and a 3000 stall converter with a 4.10:1 posi rear end with a 255/45/16 drag radial. some of you know that I recently blew another n/a motor out. I've got a s/c motor that I'm going to re-ring and re-bearing. but I might actually go with forged rods and pistons also. I havent torn the s/c engine down yet, so I don't know if I need to bore out the cylinders. but this is just a general question. IF, and this is kind of a big if. If I replace the rods and pistons with forged ones from ssm, what compression ratio should I use? I'm using an m90 type blower like most people. I can't afford a turbo setup or an autorotor. personally I'd like to step it up to 9.4:1 compression with my mpx, but I'm also considering going low compression with more boost from the m90. today I got most of the junk out of the way to pull the s/c motor from my 93 tbird. tomorrow I'll get the motor on a stand and start the dis-assembly. anyways, enough rambling. What do most of you guys run on your motors, as far as compression ratio?

03-21-2010, 03:54 AM
First I dont personally think your a....If you go in the 9 plus compression range you will either have to run low boost or run alchohol injection. And most importantly no matter what a GOOD tune. Realistically with a good tune you shouldnt blow a NA motor liek you have especially so soon.

Just seriously keep in mind whatever you do..TUNE

David Neibert
03-21-2010, 10:41 AM
If you planning to run it on pump gas (91-93 octane) then I would stay in the 8.5:1 to 9.0:1 range.


03-21-2010, 10:52 AM
For a boosted engine SSM typically builds to 8.8 compression. 64cc chambers

03-21-2010, 01:11 PM
High compression and power adders is for race cars. Not street cars. Go with the 8.8 to 1 ratio and the MPX. That will be plenty....And you will have to bore it to use the forged pistons. Minimum they come is .030