Updating early 904 - is this a suitable donor?

Hey all, I need some help in identifying the donor trans I have. I've been though other posts - but haven't found a clear answer.

I'm in the process of going through a 904 out of my '66 dart. I want to update the input/pump to run a newer converter.

I picked up a newer trans at a wrecking yard as a donor - was already removed so I don't know what vehicle it came from. Number on the case is:PK4028483-5750-0576. Couldn't find it in the list linked in other posts here.

Pulled the pump/band/shaft/clutches - and it has 5-disc clutches in it. Comparing the parts - the 5-band internals are slightly longer when assembled.

Can anybody tell me what I have with the donor and if I can do a front swap - or if I should just rebuild the donor and run with it?

Thanks for any info!