Heavy car? Go with the 440. My combo in my pickup is a 440 bored .030". KB hyper flat top pistons that come out about .007-.009". TQ 50 Erson cam (was given to me) Hand ported 452 casting heads that flowed approximately 275 cfm @ .550" on the intake, can't remember exhaust. Torker II intake, 1.6 rockers, stock crank and rods and it made 485 hp and 506 tq. I've weighed both 400 and 440 blocks and haven't come up with more than maybe 20 lbs difference, so the weight argument doesn't really hold water in my opinion. Now if you're going to stroke it, go 383 and 4.25 crank and tell everyone it's a 383. Torque makes it "feel" fast and it'll spin tires a lot and make everyone think you're awesome. JMO.