A real oddity in the area of Chevrolet small blocks was the '64-67 Nova 283 blocks. Due to the front sump pan and the position of the steering rods and related parts, the Nova block had a rather distinctive deeply recessed oil filter base, it was a screw on filter rather than a canister filter,and it had the same casting number whether it was a 283 or a 327. Supposedly it was a very thick walled casting in the cylinder areas so it could be sized for either a 3 7/8" or a 4 .00 bore. Stock and Super Stock 283 racers, of which there are still quite a few,liked the Nova block because they could bore to .065" over with few worries about wall thickness despite the large overbore. I had one around here that I got in a package deal with some other stuff years ago, and someone who came over absolutely had to have it,so I sold it. I don't remember the casting number or the date code,however. Hope they had fun with it!! The Nova had a different front sump pan, a longer oil pump pickup, a shorter pump, and oil pump drive shaft.