well i bought a 70 cutlass and i didn't notice that the block was not the orignal. so i was wondering if some one could help me out. the block has a an id number on the driver side it's 36m164494 and it has a j on the heads. so if anyone can help me out and let me know from wat car it's from.  

Someone put a later 455 into your cutlass.  Give me the number that is between the timing cover and the intake manifold. It will be to the right of the oil fill tube in that space in there (very easy to see). Take some carb cleaner and a rag and clean the shmuck off of in there and you will see a series of numbers followed by a capital letter the same size as the numbers, or a small letter about half the size of the numbers.  If you can get that for me I can tell you what it is out of.

From personal experience, the bad news is that J heads are smog heads and won't net you much performance. The good news is that it's a 455, and you can build on that like crazy.

Get me some numbers and we can go from there.

Bowser