what would be better to have custom pistons build for higher compression or to have the head shaved down some?

pistons will definately cost more, especially since you basically have to rebuild the motor when u install them. Shaving the head will cost less, but you will need a set of adjustable sprockets.

depending on the compression you want i dont recommend building high compression on non forged pistons. if you go above12:1 on a ve or 11:1 on a de be careful.

but how much could i raise the compression? does anyone know around how much the pistons would cost?

11:1 pistons from JWT are about 600.00 i think. that seems to be about the max on a de. if you want to try higher mill the head and get cam gears. i heard of a few of the 11:1 de cars have detonation on very hot days...95F+....on 92 octane gas, but not sure what the problem was. i know a lot of people do the 11:1 setup and it runs fine. the pistons are 1mm larger so the block needs to be machined.

Whenever possible, don't mill the head to raise compression. If you run an aggressive cam you may run the risk of vavles contacting pistons.

you can run higher than 11-1 compression on a street car, however you would need to retard the timing so much to prevent detonation that you probably wont notice much of an increase in power.

Originally posted by bigtom
11:1 pistons from JWT are about 600.00 i think. that seems to be about the max on a de. if you want to try higher mill the head and get cam gears. i heard of a few of the 11:1 de cars have detonation on very hot days...95F+....on 92 octane gas, but not sure what the problem was. i know a lot of people do the 11:1 setup and it runs fine. the pistons are 1mm larger so the block needs to be machined.

When Mike Pahls and I built the 3rd and 2nd (respectively) 11:1 street engines we both encountered some part throttle ping around 3k rpm.

Mike Kojima (who built the first one) worked with JWT to discover what was causing it and the issue has long since been corrected. It was a simple map change.

yeah because i was ***** build it with compression of like 10.5:1 or 11:1 but i wasnt sure of how i should do it......becuase im going to have other parts of my motor machined so i diddnt think going and milling the head would be a good idea....should i get the rebuild kit for all of the other little parts or just use the ones i have....i was thinking use the ones i have if they are not in bad shape?