If you are going to resleve the block anyways you can start with any B18 or larger block and the B18's are more plentiful. The only diff between the B18 and the B20 is the larger pistons in the bigger bores so the crank and rods are the same as the B18a/b motors. If you want to rev like a vtec you will want aftermarket rods. Or just get the B18c crank and rods. It has a slightly shorter stroke but it is designed to rev that high.