does anyone know what these big block casting numbers are and what they cam out of? The heads are square port and read 3964297. The block is a four bolt and reads 3999239 and i think it is a 72 block.

Could you double check the casting on the block. I show a 3999289, and a 3999293, but no 3999239. Also, could you check the casting on the heads. I show a 3964291, and 3964292, but no 3964297, Don http://www.chevelles.com/forum/smile.gif

I don't show those #'s either

hey,

I think you may be off on your numbers, I was on mine and it made a big difference, most of the time it's a bad stamping originally. Anyway i found a 3999289 where your 3 could be a misinterpreted 8 and its a 454 from 72-79, and the heads too, found a 3964291, where your 7 could be a misinterpreted 1, there rectangle and are for 396,402,427,and 454 from 69-70. also this website might be helpfull WWW.Mortec.com

hope this helps.