I didn't know that hemi's were that heavy. About 360's, I thought they used the same heads amd cams, just different crank mains. I know the 360 will only stroke to 408 and the 340 will stroke to 416, but I don't think that makes much difference. The 340 block I have is not a matching block. The car was a 318 originally, at least that what the vin says. I'm not keeping this a stock car anyway. I'm building it to drive around but also race. I want to get as much power as I can out the engine without juice or forced induction. I don't think I would like the 440's weight without having power steering.