part number for the bearing at the dealer is 53009180AB.

FYI, a Magnum 360 and LA360 are balanced differently---which means the flywheels are different (also the front balancer too). There may be an aftermarket flywheel that'll have different holes tapped for different size pressure plates/clutch setups. Might be one available for the LA 360 so you can use a 4500 trans clutch on it.

A nv3500 trans might be a little easier to use, but pretty sure you need to convert to a hydraulic setup on the clutch--I don't think it is that big of a deal if you can do some fab work yourself a little bit.

I have a 833OD in my truck. If you are not abusive, they will do just fine. They are strong---not as strong as a regular 833 in an iron case--but still strong enough to hold to a big block. I put 3.55 in it, first gear is pretty steep. Not sure 100% if I like those, I need to drive it more before I decide to go up or down on the gearing with my tire size (29-30" tall).