Choices depend on availability. Most shops won't know what an 1890 rear end is, since it was a made for GM only. You will have to find a grey haired trans and diff. guy who knows what you are talking about. Another option would be to put a Brownie in there. 6241 was a factory option. Would fit in place of your pump.

I will give you the phone number of the old time gentleman in Duluth I got my 4.33 two speed from when I find it.

When you get around to doing the rear brakes, the sooner the better, cups and covers are available new, no other brake parts are available. The shoes are rare, perhaps made of zink, looks like Al, everyone wants them, no one has any. To remove the Dayton wheel/brake drum assembly without having to remove it to the ground-they are heavy-use two inexpensive cable come-along. Wrap one cable around the end of the hub, where the axle attaches, and keep it there, wrap the other one around the drum as far as possible inboard to help pull the assembly off. Never have to lower it to the ground, bearings and seal are removeable from there. After you have checked the bearing tightness WITHOUT the seals, install the seals, then move the inner come along outboard and hook the top to the top of the inner frame railto help pull the assembly together. This is assuming both comealongs can be attached to the bed rail, on the outside of the bed. Be careful when ordering new seals, mine were CR, which crosses over to SK directly. I have the number somewhere if you cannot find it. Other seals, FM, for example, have a smaller piece OD steel that will not fit over the hub properly, even though they cross over to the CR number.

I'll send px when all put together, waiting on nuts now.

Ed

Last edited by EdPruss; 12/30/2018 12:58 PM.

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.