OK, 270 block and crank, 248 pistons and rods. Rods is rods, sorta'. So the issue would be difference in compression height od 270 and 248 pistons and you hope to fix that by decking the block? When you did the sonic check on the block did you check the deck thickness? It's been too long I don't remember how that made the 302 & 270 blocks taller for the 4" stroke but the blocks are taller. You can build a bad ass 248 street motor.
Last edited by Beater of the Pack; 02/04/20 07:33 PM.
