As far as I know there was not a 336, A 236? 236& 256 were limited production short deck engines. While a 248 would not be a bad choice. A rebuilt 270 Shortblock for $1000 isn't a bad rice if done well. I doubt if you could redo yours for that + time.That's where I'd go.
The 336 is a specific GMC v8 made by Pontiac base on the 370/389 was only used in 58/59.
From what I understand the block is not assembled on the 270 but it has all the parts to be and I could slap my head on it.
