1970 C10 drivetrain dilemma / advice
 

Hello all,

What I have: 1970 SWB, 6-lug, GM 12-bolt rear end

What I want: 5-lug with disks in front

What I did: Bought a 1972 parts truck for disk brakes in front, PS, PB, bench seat, rear end + other misc parts.

What's the problem? The rear end on the parts truck had been previously swapped out (unbeknownst at the time of purchase) and has what I think is a Ford 9" rearend. The lug pattern is slightly bigger than the stock GM front end (it would be nice if lug pattern in front and back were the same ... right :) )

I could sell off the the Ford 9" and get a used GM rear end (~$200).
I could buy new axles for my current 12-bolt rear end (~$200?).
I could buy new axles for the Ford 9" that have smaller lug pattern (do they exist?).
I could get spindles/brakes that match the Ford 9" (???)

This is a cost-conscious build, which is why I bough the parts truck in the first place.


WWYD?


Barry

Re: 1970 C10 drivetrain dilemma / advice
 

Are you buying 1 set of wheels and that's it? If so, you can leave it. If you're interested in changing the wheels, you can buy new axles for the 12 bolt you have and sell the 9 inch, or vice versa. The cost of the sold rear end should offset the axle cost. However if you cracked open the rear you should replace seals and bearings and that costs money too.

Re: 1970 C10 drivetrain dilemma / advice
 

I'd pull the Ford 9", sell it....and find a good 12 bolt GM diff and put that in. The Ford 9" units are popular and you should get more than enough for that to purchase a good GM unit which will suit your needs (ie: posi / 3:73 or similar).
That said, make sure you get the right one to suit your rear suspension...noting that the GM leaf spring diffs are different than the GM trailing arm diffs in their mounts, pan hard bar mount, etc.
After the switch...all other changes and upgrades get easier and stay uncomplicated.
My two bits.
Coley

Re: 1970 C10 drivetrain dilemma / advice
 

Alot of ford 9 inch rearends have smaller paterns [4 1/2 ] inch than what I assume you are looking for , the chevy [4 3/4] inch , If you are sure its a ford nine inch they sell for big money , so you could sell it and buy 2 or 3 chevy rear ends for what you get for the nine . Also know nothing is standard , these trucks were made with , 5 on 5 ,5 on 4 3/4 , and 6 on 5 1/2 lug paterns , and thats just chevy , Im sure the ford has even more variants , moser can and does make all kinds of axils to mix and match , you may be abil to have your axils drilled to the pattern you want ,,, if your axil has a posi in it Id definatley keep it

Re: 1970 C10 drivetrain dilemma / advice
 

I bought used 5 bolt axle shafts off EBay for my 12 bolt they were $40 ea. and were in great shape, because yours is a 70 this should work for you too.
9" Fords are very desirable and will sell for a good dollar.

Re: 1970 C10 drivetrain dilemma / advice
 

I'd take a pic of your 9 inch rearend and post it. Maybe it's not what you think it is!

Re: 1970 C10 drivetrain dilemma / advice
 

Dunno for sure, but I'd be awfully tempted to pull those Ford axles and have them re-drilled to match the Chevy 5-on-5-inch pattern--because of the wide continuum of axle ratios available for the Ford 9-incher, plus, after all, it IS a Ford 9-inch which = another thing to brag about!

Remember: "tempted".;)

Sam

Re: 1970 C10 drivetrain dilemma / advice
 

I would like to ... the truck is at my in-laws and I've been trying to get him to take a picture for me! They are a bit technology challenged.

I think its a Ford 9" because the fellow who sold the truck wanted to make a drag truck out of it, and it has a pair of giant Hoosiers on the back. I know that the Ford 9" is pretty popular amongst that crowd.

Thanks for all the great ideas!


Barry

Re: 1970 C10 drivetrain dilemma / advice
 

careful if you decide to do an axle swap on the '70 rear end...two possible size axle shafts that year.

Re: 1970 C10 drivetrain dilemma / advice
 

Could be a lowly 8 inch too!
I assume the in-law can count the number of bolts on the cover for you.
If he counts more than one we know it's not an 8 or 9 inch.