Big block. I'll just copy what I've said in several other similar posts. A previous member says the B blocks are only 70 pounds heavier than a small block, and I have 95 pounds, so just subtract another 25 pounds from what I've listed. Some will say do the same to a small block, and be that much lighter, but again, we're talking about a 70 pound difference between the two motors, and lightweight B parts save more weight than they do on a small block. Small blocks, being smaller all over, have smaller bores, and less room for bigger valves and ports, which is where the power potential comes from. You can also rev lower, and be in the power band sooner, giving a longer lasting motor. Also notice that a small block 4-speed would weigh more than an automatic B motor.
I've driven a crappy handling 440 Dart, but it was slammed on the ground, /6 torsions, no sway bar, and 90/10 shocks. I've driven poor handling small block B-bodies, and decent handling 440 B-bodies. If weight's your concern, A-bodies can weigh more than some big block B-bodies. We're only talking about 100 pounds from BB to SB, and there's a lot that can weigh much more than that. Considering you can use aluminum parts on a BB, I don't think there's much to worry about. Here are some numbers:
Part....................Weight savings
aluminum heads..........58#
intake..................25#
water pump & housing....15#
headers.................25#
mini starter.............7#
Total savings:.........130#
Manual steering is 37# lighter than power, and a 727 is 75# lighter than an A-833, and who knows how much A/C weighs. Small blocks weigh the same as a slant 6, and the B motors are 95# more than that, so a manual slant 6 or small block with power steering and A/C (guess 60# for that) can weigh 200# more than a 383 or 528 A/T. Relocate the battery, and that's a 50# shift from front to back, so that small block could weigh 300# more up front than your /6 or small block pig.
