Frame Question
 

I have a '66 C-10 Fleetside Long Box. My trailing arms are HASHED!!!! Rusted through and splitting apart. So, 2 years ago I purchased a '72 Chevy C-20 frame that was equipped with trailing arms. The truck was supposedly from Arizona so the trailing arms and the frame are very solid. I pulled the trailing arms off to replace the ones on my '66.

Here is my dilemma, my '66 frame is getting pretty rusty right above the coil spring mounts and it may be slightly tweaked. The story goes that my aunt had hit a rock out in the field/pasture hard enough to dent the transmission crossmember (I assume this is why my engine mount holes never line up).

What are the differences between a 66 and 72 frames?
What are the differences between a 3/4 and 1/2 ton frame?

I have the frame drawings of the 66 frame but not for the 72. Anyone know where to find them?

Just to throw another variable into the equation I have access to a '74 C-10 Fleet Long Box. I was thinking of pulling the front crossmember/suspension off of that and putting that on to get disc brakes.

Any insight would be greatly appreciated!!

Re: Frame Question
 

The 63-72 had the same frame. 1/2 ton at least. There are several threads here on the disc swap. CaptainFab seems to be the resident expert on the frames.

Re: Frame Question
 

The '63-'72 frames were basically the same whether C10 or C20. There are some minor differences, such as extra reinforcements on the C20 and C30's. Of course the '63-'66 frames are slightly different than the '67-'72 frames, but they can be easily adapted. You will notice that your C20 trailing arms have extra reinforcements riveted to them. IIRC the C20 frame may have an extra piece in the area of the coil spring mount. If you are wanting to put that '72 C20 frame under your '66 C10, it can be done. The radiator support mount will need moved. The rear cab mounts are different also. And of course the front frame horns are different, to accomodate the different bumper. Otherwise, they are basically the same. Also as I always recommend before swiitching frames, check with your local DMV as to the legal requirements on doing so in your State/county.

As for the front suspension swap, that is what I always have used on the '63-'66 trucks, the '73-'87 front suspensions. Check out the '60-'66 FAQ index at the top of the page. There is a thread titled 'Disc Brake Upgrade Reference Thread'. It is actually on the main page this evening. That will tell you everything you need to know.