Trouble mounting Chevy Cab on GMC frame

[HeloCrewChief]

Hey guys,
I picked up a 63 GMC truck short/fleet project that cab with a solid 60-63 Chevy C10 cab. Well I went to swap them out today and the rear two body bushings lined up but, the front holes are about 3 inches off on each side. Is there a fix for this? Are GMC frames different than Chevy frames? Also it has a leaf spring set up in the rear. Is that a GMC thing and dos someone make these leafs for it. Any other issues I should know about running a GMC frame with CHevy cab? Thanks for the help guys. Couldn't do it without you guys.

[padresag]

''I picked up a 63 GMC truck short/fleet project that cab with a solid 60-63 Chevy C10 cab"
what really is this trying to say or mean. please explain which was that you are going and why
ron

[markeb01]

The problem you’re discovering with the cab mounts isn’t Chevy vs GMC, it’s in the age of the cab. From what I’ve read, the 60-62 cab mounts are the same (sharing the torsion bar front suspension), and 63-66’s are the same (sharing the later chassis design). Swapping cabs either way isn’t all that uncommon, but the cab mounts will require relocation.

Leaf springs in the rear are a GMC feature on certain models/years. Any competent spring shop can restore or rework leaf springs, and leaves can be removed or added to change characteristics. The biggest concern I would have with the cab swap is whether or not you can get it legally registered. This may be easy or impossible depending on what state you live in, and if you have the pink slip for both the cab and the chassis.

[aerotruk63]

You can drill the holes through the floor to match up to the frame. The cab mounts have two horizontal flat portions to them. You would be required to drill into the inner sections of the cab supports in order to mount the cab to your 63-66 frame.
1963-66



1960-62

[jonzcustomshop]

there are also a couple threads with pics discussing the diferences between the 60-62 mount and the 63-66 in the faq section.
gm actually still used the wide 60-62 mount until 66 on the big trucks.

pretty much all 63-66 gmcs were leaf, 60-62 had the coil on the lighter trucks

[HeloCrewChief]

Padresag,
''I picked up a 63 GMC truck short/fleet project that cab with a solid 60-63 Chevy C10 cab"
what really is this trying to say or mean. please explain which was that you are going and why
ron

That was just a typo. Sorry about that. Had the two dogs bugging me while I was on the computer. Thanks for all the information guys. I have messed around with many Chevelles and Novas but, this is my first truck and I'm quickly learning while they are very easy to put together, there are many different configurations of how they came from the factory. I figured that I could re-drill the front holes as they run on the same support. Are those recessed areas in the floors where the bolt heads sit pressed or welded in as I would like to use them with the new holes? I have the pink slips in my name for both trucks. The only thing I'm concerned about is the VIN on the chassis not matching up with the cab. I know in the Chevelle world guys swap out rusty chassis all the time and never have an issue with that though. As far as the leafs are concerned, do you guys recommend running them. I don't ever recall seeing a truck running leafs on here. Thanks for all the information and sorry for all the questions.

[padresag]

springs are std to gmc. what you were trying to say is that you want to put the chev cab on the gmc frame or that the chevy cab is already sitting on it. the thpng to do is just move the mounting holes over.
just go into a mvo and ask them what the procedure would be for registration in this situation. they are not going to paint an x on your back and remember anything, so just go and ask. I can remember when I was a young guy and just got my 32 chev sedan on the road(271 olds , full engel cam, 11;1 m/t pistons, 6-97's on top and she wouldn't idle under 1800) I was running full slicks and sitting on an apple box. I was driving through Brighouse(richmond,b.c.) and had to stop for a train or tram. looked to my left and there was a cop sitting at the stop sign looking right at me, and you know the look. traffic started and I knew what was going to happen. the pollice station was just to the right, so I pulled in and parked my car, got out when the cop stopped and looked at me and I just said that I have to go in there(the police station which I did, asked a stupid question and then left and got in my car and drove away.
the one thing about a GMC frame of those years is that no one can find where the ser. #'s are on them or if they were ever stamped on them. the rear springs will be the only give away that it is a gmc frame
ron
ron

[LostMy65]

I mounted my Chev 65 cab on a 62 gmc frame.
I just moved the floor holes out to line up with the 62 frame mounts.
You'll just need to move yours in.
Posted via Mobile Device

[Captainfab]

It sounds to me like you have a '60-'62 Chevy cab sitting on a '63 GMC frame. Are the front cab mount holes too far apart? Are there 2 holes where the master cylinder would be? If so then you have a '60-'62 Chevy cab. The VIN on the cab will tell you for sure also.

As was already said, just drill 2 new holes, and move the dished washers over. They are spot welded to the floor.