The Stovebolt Site Forums The Shop Area Driveline Updated Rear Axle for 55 First Series

I have a 55 first series 3100 chevy truck and am planning to install a n early sixties C-10 6 lug rear end in order to get a high gear ratio. I don’t have the original rear end that came with the truck so I can’t use those original leaf spring perches. Where can I get some new perches to weld on the replacement rear end that I will be installing? Thanks in advance for the feedback and assistance.

Most vendors will have the saddles to mount your new rear end. Classic Parts lists a complete "Rear axle conversion kit" including mounts, u-bolts and shock mounts part number 93-311 that will work for a 55 first series

I don't think you will gain much going to an early 60's rear end. It probably has a 3:90 ratio & yours is probably 4:10. I don't know what engine you have but some of the 67-72 c10's had 3:08. They may be to wide for your 55 & i'm not sure the original engine will pull it.
What about changing to the the gears in yours to the 3;55 gear set?

George

Thank you. Where could I pick up some quality 3:55 gears?

Hi and welcome to the site! The late 60s C10 trucks were great for the AD pickups. Just the right width. Many of those had ratios starting at 3:07 (which is what I have). Mine was out of a 1969 C10 which had been a really nice truck before somebody decided to drive it upside down. You can even use the same emergency brake setup simply by modifying things a wee bit. If by chance you're swapping the transmission to the T5 look for the T5 which has the gear chain beginning with 4.03 and you'll have an overall first gear ratio of 12.08 and that will let you still use your pickup as a genuine pickup (the first 3 gears will feel exactly like the original setup) plus drive at 60 mph at around 2000 rpm, 65 at 2100 rpm, etc. You'll need to cut off the coil spring mounts the late 60s C10 trucks came with, discard the panhard bar, smooth the axle and use any generic spring perch piece (or you can use the round adjustable collar like I did and weld when you get your pinion angle correct. You'll even get to use the same brake line hookup and wheels. When you're welding those perches, just use common sense and weld 1/2 inch or so on one side then move to the other side while it cools, return and keep that up so you don't risk warping the housing (which I've seen people do by just running a solid bead). Easy work if you can find one. Good luck!

I have done a few axles now with perches from the trailer supply shop, but I am not familiar with what you are describing here. Can you elaborate or give us a link?

Like this:

https://www.amazon.com/Clamp-On-Leaf-Spring-Mount-Pad/dp/B01N9VQ6BQ

Makes the work of setting, adjusting, re-adjusting, etc a lot easier. And as far as welding you can just weld the southern hemisphere of the mount if you think you might want to adjust your pinion angle later. That gives you plenty of strength.

Those are pretty cool. Thanks!

I looked on Speedway's site and didn't find them. I'll bet that someone used them and didn't weld to the axle and spun the axle housing. They probably discontinued them to protect themselves from the dumb___s who don't install them correctly.

https://tinyurl.com/yp8ks7bh

Above is a link to them on Speedway's site. Actually Speedway is one of the companies who sells them branded under their own name (Speedway Motors). Nearly everyone sells them and they've been available for around 40 years. The instructions you get with these are very clear about welding them before using them. Not to say some nitwit didn't just clamp them on and go. It is impossible to predict nitwits.

Several years ago a friend used silver bearing solder to attach these to his axle (that solder as I've mentioned here numerous times will work fine with ferrous metals as long as you understand the principle of cleaning and fluxing). I asked him a couple of years ago and he said they were still doing fine...no problems. Most silver bearing solder has a tensile strength of something over 10,000 PSI (some as much as 18,000) and as you can see there are several square inches of metal to use in this case. You can also braze them in place if you can use an oxy-acetylene rig, but you do have to heat things up more that way. Silver bearing solder melts/flows at a mere 450 degrees. Good luck!

I assume the 55 first had a closed driveline? If so, what transmission is being used with this 60"s rear axle?

If it is a 1955 first series it came with an open driveshaft, one of the few differences from 1954/