For Those Doing Disk Brakes. 60-66

[Mjminino]

Yeah earliest year here in Omaha is a 77 and I'm sure there would be some fabrication tonuse that rear end?

Could I take my current spindles to a machine shop and have them drill new holes? And just use captian's disk brake plates?

[Blu64c10]

Originally Posted by Mjminino

Yeah earliest year here in Omaha is a 77 and I'm sure there would be some fabrication tonuse that rear end?

Could I take my current spindles to a machine shop and have them drill new holes? And just use captian's disk brake plates?

Mjminino,my build thread shows how I filled my 6 lug pattern and redrilled for 5 lug, any machine shop should be able to do this.

http://67-72chevytrucks.com/vboard/s...=642354&page=2

[Captainfab]

Yes you can have your original 6 lug axles plugged and redrilled to 5 x 5. I would only do that if the bearing surfaces are in excellent condition. If you need new axles, I believe you will have to go with 30 spline axles, which means changing the spider gears also. You can change the entire differential for a 10 bolt or 12 bolt up thru '86 in the C10's and '87-'91 in the R1500's. You will have to cut off all the original spring pads and shock mounts and weld on trailing arm mounts (I make those) and also the panhard bar mount. Those will all be 1.5" wider than your current 12 bolt. If you were able to find a '71-'72 12 bolt it would also be 1.5" wider.

[OldGMJon]

I was hoping to switch a complete donor 80' Chevy C30 front cross member onto my 66' GMC 2503. Are the C30 cross members different in any significant way for those years? Would a rear end swap go in cleanly as well? Maybe the front (disk/power) cross member would be a better fit on my 65' C10 lwb with 350 & a 3 on the tree? Opinions?

Originally Posted by Captainfab

Yes. You can change the entire differential for a 10 bolt or 12 bolt up thru '86 in the C10's and '87-'91 in the R1500's. You will have to cut off all the original spring pads and shock mounts and weld on trailing arm mounts (I make those) and also the panhard bar mount.

[Captainfab]

A '73-'87 C30 front crossmember will fit your '66 GMC just fine. The C30's are basically the same as a C10 or 20. You will have to drill one hole on each side and elongate one hole each side. I don't remember the measurement but I do believe a '80 C30 differential will need the spring pads moved to bolt up under your GMC. It also depends on whether the C30 is a C&C or a pickup.

Originally Posted by OldGMJon

I was hoping to switch a complete donor 80' Chevy C30 front cross member onto my 66' GMC 2503. Are the C30 cross members different in any significant way for those years? Would a rear end swap go in cleanly as well? Maybe the front (disk/power) cross member would be a better fit on my 65' C10 lwb with 350 & a 3 on the tree? Opinions?

[OldGMJon]

Originally Posted by Captainfab

A '73-'87 C30 front crossmember will fit your '66 GMC just fine. The C30's are basically the same as a C10 or 20. You will have to drill one hole on each side and elongate one hole each side. I don't remember the measurement but I do believe a '80 C30 differential will need the spring pads moved to bolt up under your GMC. It also depends on whether the C30 is a C&C or a pickup.

Thanks for responding Captn...
You're speaking of the Leaf Spring pads that need moving I gather?
The C30's are flatbeds...
I thought why not just install the whole drivetrain, front sup., rear end, trans, and engine from the 80' C30 into the 66' 2503.
Will I need to use everything including; the engine mounts, the steering box & pump, the steering column, etc.?
Are the chassis' the same length/will I be able to use either's driveshaft?
What is the gearing in an 80' C30 trans(4sp/lowest granny) and rear end?
Will this switch be worth the effort?
I appreciate hearing from the guys in the know...thanks again Captain.
jon
ps: the flatbed on the 80' C30 will look perfect on my 64' C30 and to complete the 66' GMC 2503 I got a 65' GMC I1500 for most other parts I'll need.

[Captainfab]

Yes I am talking about the leaf spring pads. You can use as much or as little of the donor '80 C30 as you want. It's hard to say what the differential gears are. I would think 4.10-1. There are a few different wheel bases with the C30's so it's hard to say about the driveshaft. If you will be using the SM465 from the '80 C30, you might be best off to use the '80 driveshaft? Just have to take a look at it and see what will workout best. Yes I do feel it is worth the work for the conversion.