The Olds Rocket V8 was the Golden Choice in early Kaiser conversions. After all, Kaiser used (mostly) the same Hydramatic and negotiations were made to buy engines from GM.
However, at the National held at Oshkosh, someone showed up with such a conversion. I viewed it with interest, but I was put off by how much cutting to the chassis and the driver's side exhaust manifold was done.
Well, if you have a Hydramatic car and have an early Olds V8 with Hydramatic, I suppose you could rationalize putting it in a Kaiser. However, there are much better and more modern choices for engine and transmission. I am not even limiting consideration to SBC V8s either. You know all those big 79-83 square bodied Olds and Buicks? Well they mostly came with 307 c.i. Olds V8s with Turbo350s or later, 200R4 automatics. The 307/350/400 Olds V8 (all the same in external size) have some design features that facilitate installation into narrower frames. For instance the plugs are angled upward and the exhaust manifolds angle down towards the side of the block which makes the engine slightly narrower than a SBC.