UGH C20 rear end dilemma

[Mathew21]

OK some of you may know I bought a 65 C20 327/Th400 recently. Well I finally got the chance to drive it the other day. The engine runs excellent. The truck handles great. I'm impressed how well the power drum brakes stop. I plan on this truck to be my daily driver weather permitting April-November.

Now the bad part. I want to drive faster then 45 mph without the rpm's roaring. I believe but have not confirmed yet that my Eaton HO52 has 4.57 gears. Even it had 4.11 I don't think it would help much. I plan on swapping the TH400 for a 700r4. But I don't think that will get me to where I want to be. I really want to be able to cruise comfortably at 65 mph.

After doing much reading I can't find the perfect match 8 lug axle with the same Wms as mine. (approximately 65"). I would like to keep the truck 8 lug. the only thing I found close would be 14 bolt from a cab and chassis truck. (63.5") then I would have to redo the axle to accept coil springs.

I did find someone local to me that has a 6 lug 12 bolt out of a mid 60's C10 with 3.73 gears. He also has a 5 lug 10 bolt out of he thinks a 1972 C10 with 3.42 gears. both are reasonably priced.

I'm just trying to decide do I want to take my C20 and make it a half ton. I do plan on going with disc up front sooner or later so I could change over the front to match the rear if I do swap to a different bolt pattern.

I know the decision ultimately lays in my hands. I'm just
looking for some advice.

Here's a link to my truck in question. http://67-72chevytrucks.com/vboard/s...d.php?t=615628



Sorry for the long post, Matt

[rickywideglide]

im in the same boat, have 64 with eaton rear with 4.56 gears, i picked up half ton rear and crossmember to do switch . i plan on using truck as daily driver as well so i think for me i will do rear first seems the easiet to me

[Mathew21]

Originally Posted by rickywideglide

im in the same boat, have 64 with eaton rear with 4.56 gears, i picked up half ton rear and crossmember to do switch . i plan on using truck as daily driver as well so i think for me i will do rear first seems the easiet to me

So if I swap to a half ton rear end I need to change the cross member too?

[rickywideglide]

yea if you want same lug pattern in the front

[Mathew21]

Originally Posted by rickywideglide

yea if you want same lug pattern in the front

OH okay I misunderstood you. I was thinking the rear crossmember by the axle.

[TommyDuncan]

Use a DANA 60 out of a same generation GMC ¾ton. They can be geared as tall as 3.54.
Not a bolt in but the width should be right and it's 8 lug. I can measure whatever you need on my 62 if it helps.

[Captainfab]

Yes a Dana 60 from a '67-'72 would be a direct bolt in, but those aren't exactly easy to come by. The '68-'72 Dana 60's behind a big block and an auto trans had the 3.54 gears.

Depending on what tires and wheels you are running the '73-'87 14 bolts can work. I do make trailing arm mounts specifically for the 14 bolts should you decide to go that route.

[Mathew21]

Originally Posted by TommyDuncan

Use a DANA 60 out of a same generation GMC ¾ton. They can be geared as tall as 3.54.
Not a bolt in but the width should be right and it's 8 lug. I can measure whatever you need on my 62 if it helps.

Thanks for the suggestion and the offer to measure the rear end. Parts for these trucks around here are like a needle in a haystack.

Originally Posted by Captainfab

Yes a Dana 60 from a '67-'72 would be a direct bolt in, but those aren't exactly easy to come by. The '68-'72 Dana 60's behind a big block and an auto trans had the 3.54 gears.

Depending on what tires and wheels you are running the '73-'87 14 bolts can work. I do make trailing arm mounts specifically for the 14 bolts should you decide to go that route.

Thanks for the information. I did read that I could use a 73-87 14 bolt and I also did read you make the parts to do this. Right now I'm running a set of factory steel wheels off a 90'ish Chevy truck. I only have about an 1.5" between the tire and inner wheel well lip on each side.