Hey guys. Right now my stock '69 C10 has its original 12 bolt with 3.08 gears and peg-leg open diff. I was planning on swapping to 3.73 gears and adding a posi when I started thinking maybe I should just swap in a 9.5" 14 bolt instead.

When I still had my K5 I blew the stock rear end all over the trail and swapped in a 14 bolt with ease and never had a hint of trouble with it afterward. However that was with a leaf spring rear suspension, not a trailing arms suspension like my current truck.

I am also interested in the swap because I also plan on towing an RV in the near future and don't want to worry about strength issues with my stock 40 year old 12 bolt.

I know where I could score a low mileage 9.5" 14 bolt complete with brakes, 6 lug axles, 3.73 gears, and posi for less than $100. Which would be hundreds (if not a thousand) less than rebuilding my 12 bolt.

My question is how hard would it be to swap in with my trailing arm rear suspension?

I am not interested in swapping to a leaf spring setup. I already have a Air Lift adjustable airbag setup along with new shocks, adjustable pan hard bar, trailing arm bushings, etc. Plus I like the nice and smooth ride the trailing arm setup gives me when cruising.

I am sure some of you have done this to your '60-'72 GM trailing arms trucks, so lay it on me, what's involved?

Thanks guys!!

Just need a welder, grinder, a tape measure, patience and most importantly pay attention.


Do it! I think for 100 bucks you can't go wrong with the newer and bigger axle.

Just cut your old brackets off and weld them to the new axle.... it's not hard at all.

Heres a kit (http://www.classicperform.com/Store/1960_1972_Chevy_Truck/6072DRCK.htm) to do that

That kit looks like a good idea. It make the track bar longer by bolting it to the axle u bolt instead of the welded bracket on the axle tube. That requires very little welding. You can also find 5 lug axles for that 14 bolt SF if you decide to convert the trucks front end to disc brakes later.

Heres a kit (http://www.classicperform.com/Store/1960_1972_Chevy_Truck/6072DRCK.htm) to do that

I already have that kit, except mine is from ECE.

The axle tube diameter is what worries me about the 14 bolt (3.5") vs. the 12 bolt 3.0".

Yea does not really say the tube diameter. I think Speedway Eng may have axle brakets for a reasonable price.

some easy work with a grinding wheel would make that 3" cut-out into 3.5". i've done it many times just take a sharpie and make the hole wider, then grind off the sharpie marks, then keep checkin the fit until it works.

What about the u-bolt clamps, the bolt spacing will be wider.

custom u bolts are easy to get from napa or a quality parts place. there is a new memebr here from burk spring company in indy.....

there are ways to make your 6 lug disk brake with 90% junkyard parts.


try www.67-72chevytrucks.com



if all else fails pm mj, he should know.