Looking for a complete early A engine (POLY)

[ImperialCruiser]

I picked up a 55 Plymouth Belvedere and would like to replace the flathead with a period correct V-8. Ideally I would like to find a 241-260 but would consider anything that bolts in. Anyone have such a beast? I will be gone for a week so don't think I'm ignoring anyone. I'd also like to find a 3 speed trans with overdrive for the same car.

 

[cudamark]

I have a late 50's core short block that I believe is a 315 if that helps any.