OP, can you remind us what pistons you have now? Did I see where you have had them pressed on the rods already? The 318's have the problem of low CR to start, and you are making that lower with 360 heads. Refer to the 1st paragraph of where you are heading in post #333. Not a good grocery-getter CR..... it is going to be low if this is the combination it sounds like. Get some piston info out here so we can compute that CR.