Here is some info on pistons using 5.7 rods. Use KB100 flat top pistons with 5.7 rods and 76cc chamber heads to have a 9.58 compression ratio. Use KB102 with 5.7 rods with 64cc chamber heads for a 9.67 compression ratio. Like was advised do a search on this site on building a 383 cid. The block will also have places that will need to be clearanced.