Its a World Product block the shortblock 572 was done by Muscle Motors with B1s, last i weighed it was with a indy headed 440 = 2670 since then i also replaced with strange brakes Bobs Profab control arms and a stock lightened k member, ill reweigh this spring and i also replaced the front tires and wheels with runners, should total couple hundred off to equal about 2500#, at this point this thing is going to be pants shitting too fast for me lol