So far I have come to find that the shop now claims my 193 heads are actually 64cc and that all the pistons out there will be to much compression to use regular unleaded, most will be boarderline with super unleaded. He says that with a zero deck and forged pistons we need to be at -30cc minimum and -35cc would be ideal. Whats the opinion from you guys on this? I need to do some CR math and check him....maybe after I get back from taking my family to the mall. If you guys know of a piston that will work for me with a 5.7" rod in a 383 combo please chime in. The machinist is now telling me that this plan is a no-go and that we need to stop and admit that this needs to be a .030" over 350 and leave it at that. I hate to settle for something after I have planned and dreamed about the outcome for 3 months.