do not let any budy give you crap on this .yes make sure hedders fit but i make mine. so her it is 400 longer rods and 60 over 4.1/2 strokewill make 525 so you can build it more this is the same block that gm s 10.200 block is base off but walls are thicker .i can help you here i have bulit the 526 and with the bow tie or donovans 10.200 572over 620 my last engine dyon out at 800hp and 750 torque i t made it at 6500 rpm