68 Barracuda slant 6 and auto trans - cheap

It has the long water pump bypass hose which means it's a tall deck RG block. Probably a 225, but possible it's a swapped in later 198......but doubtful. If you look behind and under the alternator, there is a small ledge of the block that sticks out right where the head meets the block that' probably like 4-5" long. It has a series of stamped numbers on it and the engine size will be there. Very probably a 225.

Here is the ID pad with the head removed, but it will be evident and readable with the head installed.

ID PAD.jpg