1970 c20 subframe swap

[c20pickup]

i currently have a 1970 c20 chevy with front drum brakes that is being restored at the moment. yesterday i purchased a 71 chevy c20 longhorn with front disc brakes. what is all involved in swapping the 71 discs t0 my 70's drum brakes. could i just swap complete subframes from truck to truck?

[WIDESIDE72]

Yes, but you will have different size lug nuts front and rear, unless you swap the rear axle as well. I believe the drum brake trucks used 1/2" studs and the disc trucks used 9/16". If you have the donor truck it makes it a lot easier than making multiple trips to the parts house or wrecking yard. You will need the proportioning valve and lines from the 71 due to the disc brakes.

What condition is the Longhorn sheetmetal and rolling chassis in? If sheetmetal is rusty or otherwisse not worth saving, How about pulling it all off, cleaning and painting the chassis and serting your 70 sheetmetal along with the 8-1/2' bed (you might be able to use your 8' bed and the longhorn extension piece if its salvageable.)
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[c20pickup]

Originally Posted by WIDESIDE72

Yes, but you will have different size lug nuts front and rear, unless you swap the rear axle as well. I believe the drum brake trucks used 1/2" studs and the disc trucks used 9/16". If you have the donor truck it makes it a lot easier than making multiple trips to the parts house or wrecking yard. You will need the proportioning valve and lines from the 71 due to the disc brakes.

What condition is the Longhorn sheetmetal and rolling chassis in? If sheetmetal is rusty or otherwisse not worth saving, How about pulling it all off, cleaning and painting the chassis and serting your 70 sheetmetal along with the 8-1/2' bed (you might be able to use your 8' bed and the longhorn extension piece if its salvageable.)
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the longhorn sheetmetal is basically a total loss, will need cab corners, rockers, floorpans, and new doors at the least. plus i already have my 1970's chassis painted up with a new motor sitting in it so using the longhorn frame is sorta out of the question (tho i did thing about it) if th wheel studs are different would i be able to pound the old studs out and press new ones in?

[WIDESIDE72]

Originally Posted by c20pickup

the longhorn sheetmetal is basically a total loss, will need cab corners, rockers, floorpans, and new doors at the least. plus i already have my 1970's chassis painted up with a new motor sitting in it so using the longhorn frame is sorta out of the question (tho i did thing about it) if th wheel studs are different would i be able to pound the old studs out and press new ones in?

I looked into it when I was thinking about adding discs to my 70 longhorn. I could never come up with a direct replacement. I found info here on the forum. I just wish i could remember where!
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[c20pickup]

Originally Posted by WIDESIDE72

Yes, but you will have different size lug nuts front and rear, unless you swap the rear axle as well. I believe the drum brake trucks used 1/2" studs and the disc trucks used 9/16". If you have the donor truck it makes it a lot easier than making multiple trips to the parts house or wrecking yard. You will need the proportioning valve and lines from the 71 due to the disc brakes.

What condition is the Longhorn sheetmetal and rolling chassis in? If sheetmetal is rusty or otherwisse not worth saving, How about pulling it all off, cleaning and painting the chassis and serting your 70 sheetmetal along with the 8-1/2' bed (you might be able to use your 8' bed and the longhorn extension piece if its salvageable.)
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the longhorn is also missing its bed, so basically its a donor truck for now, hate to do it to a longhorn but money doesnt allow for buying a new bed and replacing rusted sheetmetal. i may keep the frame however for a future project

[SS Tim]

Here read up on the various factory brake swaps.
http://67-72chevytrucks.com/vboard/s...68&postcount=4

If you wouldn't mind I'd like to see the SPID on that Longhorn.

[SS Tim]

Read these for the rear stud issue solution.

http://67-72chevytrucks.com/vboard/s...d.php?t=543067

http://67-72chevytrucks.com/vboard/s...d.php?t=543067