I took my 396 block to the machine shop last week. I got a 402 back. They had to bore it .030 over. My next concern is compression ratio. 396 pistons .030 over will give me the stock 10.25:1 ratio. I think that is a bit high for todays gas, but I like the idea of the power it will make. Stock 402 pistons will give me around 9.0:1 compression. Good for power, but I think I will always wonder 'what if?". Any ideas or suggestions?