The Stovebolt Site Forums The Shop Area General Truck Talk 47-53 vs 54-55.1 frames

Has anyone mounted a 47-53 cab and front clip on a 54-55.1 frame?

I know there were some significant changes in 54, but I don't know if the cab to frame mounts were the same style and location on both generations of frames.

Does anyone have any info on this?

Reason being I have a line on a good 55.1 frame that has no body, and I'm curious if I'll only be looking for a 54-55.1 cab to put on it, or if I can drop on a 47-53 with no mods.

From what I can tell by looking at the FAM diagram for the '54 frame, the rear cab mounts are similar to the front mounts (rubber donuts and thru-bolts) instead of the shackle type rear mounts on the 47-53 body. A couple options come to mind for what you're considering.
1. Drill and reinforce the floor of the 47-53 cab for the later style rear mounts.
2. Remove the later style rear brackets from the frame and drill for the shackle rear mounts for the earlier cab.

I think #2 would be the easier route if you wind up with an earlier cab.

Are you sure that the FAM diagram was for a 3100?
All of the vendors are selling the same mount parts for '49 through 55.1 for rear cab shackles.

It would be difficult to mount a '47-'48 cab on a '49-'55.1 frame. You would need to drill some new holes in the bottom of the cab and re-enforce that area to hold the weight. As far as I know, any cab from '49-'55.1 will bolt right on to a '55.1 frame. The real problem is trying to mount an earlier bed to a '54-'55.1 frame.

Yep. Section 2, Sheet 2.00. Models 3100.
It shows brackets riveted to the frame extending outboard just to the rear of the middle running board brackets. I just went out and looked at my frame, and that's exactly where the holes for the shackles are on my frame. Section 2 Sheet 1.00 (Models 3100) also references those brackets with a pointer that says "Body Bracket Instruction, Sheet 8.01.
Those outboard brackets at the rear of the cab do show two holes (each) that look like they might match where the shackles mount on 49-53 cabs, so may not require modifications, just some sort of spacer and pads. I have not seen a 54-55.1 cab to compare though.

You are correct on the additional work needed to convert the 47-48 cab from center rear mount to corner shackle rear mounts. I don't think that's a huge issue though as the floor is flat in the required location for the corner shackles (unless the 47-48 cab has more there than would seem necessary.
Also agree on the problem mounting an early bed on a 54-55.1 frame.

To install later model rear cab shackle mounts on 47/48 cab requires some special shaped sheet metal reinforcements or braces, possibly available as repair parts.

To install 47/48 cab on later frame it either bolts on with the original 47/48 center mount, or two 3/8" holes need to be drilled in existing frame crossmember at back of cab then it bolts on..

I thought 54/55 had rear cab shackle mounts like 49-53? The assembly manual pictures you reference with different mounts are they for a panel truck or suburban?

The sheets (1.00 and 2.00) don't differentiate between pickup/panel/suburban, so it's possible the outboard body brackets shown are only for panel/suburban, but there are no notes to indicate that, although sheet 8.01 only indicates 3105, 3106, 3107, 3112 and 3116 models (all long body types), and not 3104 (pickup). I haven't been under either a panel or a 54 to look at the frame.
So it's likely you're right about the 54-55 having rear cab shackles.
Sorry for the excursion into left field on the body mounts.

I didn't realize the bed mounting would be different. I had thought the roll at the top of the sides was the only major change. Did they change the amount of cross sills, or where they were mounted or something?

54 and 55.1 3100 pickups do have shackle mounts in the rear, just like the 49-53. As stated before, your problem would be the bed.

So it looks like the frame kick up is less on the '54 to deal with the lack of mounting blocks since they are mounting the sills directly to the frame. Seems like the only issue with mounting a '53 bed on a '54 frame would be to get the height correct

Mar K has a pdf about putting a '54-'55.1 bed on an older frame and shows the different heights in the kick up portion of the frame.

It looks like there won't be an issue mounting an earlier bed on a later frame other than possible having to redrill the front bed mounting holes.