[Steve@OldSub.com]

Originally Posted by anythingonwhlz

I just got a 1950 GMC 1/2t SB 3100

That would be a very unusual truck. 3100 is a Chevy model designation. A GMC 1/2-ton would be a 100.

Originally Posted by anythingonwhlz

I would like to switch to a 5 lug wheel pattern,so what rear end would bolt right up to my new 1950 GMC w/ minimal if any modifications.

Most people swap the rear from a Camaro or a Chevelle or maybe an S-10 4x4. Others will suggest a Ford 9 inch or 8.8 but those will not match the proposed lug pattern on the front.

If there is a 5-lug rear that will simply fit without modifying the mounting pads I don't know which one it is.

Originally Posted by anythingonwhlz

I would like to remain drums all the way around.

Do you have the hubs, drums and backing plates to convert the front? If not it might be cheaper and certainly easier to find parts to convert to disk on the front.

Originally Posted by anythingonwhlz

And also can I just switch to 54 drums in order to change the front to a 5 lug wheel pattern and will that be a direct swap in the front?

You need to switch the bearings and the backing plates too, and may need to redrill the holes in the backing plates. Its been many years since I last did this swap and don't remember the details.

I prefer a disk brake conversion because I believe it results in a safer vehicle using easier to maintain parts and if you shop carefully does not cost a lot to do.