PISTONS The F54 motors with P79 heads ('81-83) have flat-top pistons. All other L28 motors(N42,N47,P90, P90a) came with dished pistons. In a performance engine, flattop pistons create a higher-quench mixture and allow for higher performance combustion chambers. Dished pistons are usually used to lower emissions.

Came accross this fromthis website.

My question is now... are the pistons the same from non turbo dished to turbo dished ? i know the rods are and the rings are differnt and the oil pump what elese ?

Turbo 280's get dished pistons. Non turbos have flat top pistons. The dished pistons lower compression to keep the turbo motor from self destruction. Flat top piston would increase compression, and depending on head/block combo increase performance due to increased compression ratio. If done right. What was the rest of the thread about? Sorry to who ever wrote it but they are wrong. Chech the C/R of any most OEM Turbo motor, and it will be lower than the N/A counter part. :devious: