The Stovebolt Site Forums The Shop Area Driveline 1950 3100/3600 Rear End

Ok, so strange question but looking for ideas and possibly pictures…. What I have is a project I picked up, previous owner has what looks like a 3600 frame, under a 3100 body etc, he added a 1980-4 Camaro 10 bolt rear end that was put in under the leaf springs and other questionable decisions… looking to see what you all might suggest or have ideas on how to improve.

Yes there were some good suggestions in previous post I had, just looking for more, what I have done is pictures below, always looking for improvements and modifications.

Yes this is a project driver truck not a track truck.

Hy dogdaddy, these pictures look familiar, the first thing I noticed was the line to the rear brake tee, there is a solid line from the frame to the bracket on the rear axle, this line needs to be a flex line (rubber) from the frame to the bracket on the rear axle, this installation creates a very dangerous situation, the rear axle does move up and down relative to the frame it will fatigue this solid line and break it causing you to lose your rear brakes if you have a dual system master cylinder, if you have a single system master cylinder you will lose all your braking, that would be the first thing I would fix!

I'm not sure what you are trying to change/improve? What year(s) are the parts from or trying to end up being?

Assuming that the frame is a 3600 (narrow at the rear compared to the 3100 frame) I don't think the cab or front end is different between the two frames but the bed to frame mounting points are different among other things.

I assume that the rear axle change was done to achieve a different axle ratio but what is the drive train in front of the axle? The 3600 had a two piece drive shaft with the front being enclosed and the rear portion being open. Width of the axle and resulting tire relationship to the bed/fenders is important but not apparent from the picture provided so far. It appears that there may not be shocks on the rear axle, if that is correct it is something you will want to address.

Yes you are correct, have asked the question before but in a different way, still trying to address issues. Yes I have converted to a 2 pot system, and converted front to a disc brake system. The driveline is almost completely out of an 80-84 Camaro. 305 c.i. Turbo 350, one piece drive shaft, 10 bolt rear end, The bed mount is irrelevant to the question. Yes I will eventually address the brake line issue, not a problem at the moment. No shocks yes, but I have addressed it in the aspect of using a set of helper bags on top of the springs and mounted to the frame.

I guess I just need to visit a suspension shop and get feedback there, thanks

dogdaddy - Yup to this being the 2nd time you've asked for suggestions and help on this topic.

There was a lot of good "improvement" advice given in your first post on this subject - 1950 Chevy 3100 Rear End Quandry.

It doesn't seem like you've addressed any of those suggestions, nor do you indicate clearly what outcome you are going for, so it's hard for anyone to offer more than we already have. Changes previously suggested all will have at least some effect on your trucks stance and you haven't said if that is acceptable or not in your plans???

Best of luck with your visit to a suspension shop.

PS - On your addressing the no shocks issue, using a set of "helper bags on top of the springs and mounted to the frame" seems most unlikely as there just isn't room for such equipment without making other changes (changing to taller spring shackles and/or higher arched springs as was previously suggested in your first thread).

dogdaddy - I see you have edited your first post in this thread, with added information and more pictures (3 - 5) of what you have done. This very much helps clarify your current setup so please ignore my comments above since we now have a better idea of where you are at.

Now that we can see what you have done to address most of your previous conditions, how about letting us know more in detail what your desired outcome is?

Understood it's a "project driver truck" and "not a track truck", but are you looking for a firm "truck" like ride, or something more "comfortable"???

BTW - I would definitely get the previously described "brake line" issue resolved to allow for proper axle movement and preventing brake line failure.

Thanks Gdads51, yes I will address the brake line issue eventually. What I am looking for are ideas on what other “shade tree” mechanics have done to address putting a late model rear in these trucks, not necessarily a high budget build version. As you can see I have chosen options for a budget build. Ride choice is comfortable not farm truck suspension but also not road course style. Things I am looking at are ideas on the mounting of the axle below or above the leafs. Also the 10 bolt has 2 ears on top for trailing arms? Possible ideas on attaching these to 3100 frame…

dogdaddy - On your questions concerning the axle mounted above or below the springs, the deciding factor may be the desired ride height of your truck. The way they are mounted now gives you a higher overall rear stance, where switching the axle to above the springs will significantly reduce your rear ride height and possible remove sufficient axle motion in the process. Your choice depending on your goal.

On the use of those existing axle upper "ears", I would say no if you are sticking with the leaf spring set up. They will serve no useful purpose. Those were originally designed as the upper two points of a factory 4 link suspension system used in GM A and G-body passenger cars. Below is a screen grab of an original A-body rear suspension showing the 4 links and all that made that system work. I'm familiar with the design as it's what is currently residing under my other half's '66 Chevelle.

I'll let others catch up on your new info and offer their suggestions from here.

why not look for a 3100 unmodified frame?

Would be an option but if I go that far I would start with a more modern replacement frame s10 or aftermarket but for those of us on a budget I am just trying to work with what I have and not recreate a stock truck.

Just to follow-up on Gdads51's comment regarding the axle over vs. under the springs. Looking at your added pictures if the axle was on top of the springs it appears you would have almost zero suspension travel before the axle contacts the frame. I do not beleive that mounting the axle under the springs as currently mounted creates any major concerns.

Got any pics of your truck? How stock is it now?

BD - You can see pictures of the previously reported condition (pics 1 and 2) as well as the current configuration (pics 3-5) in his post above.

Thanks for this feedback, observations I appreciate and didn’t think about

whole truck

The pictures in my original post are of of the obvious alterations by the previous owner, the more I dig and ask others the more I learn of all the modifications the previous owner applied

I.e. 1950 3100 body/3600 frame/1980’s Camaro driveline

Some shots of it currently

I've got a 1952 3600. I want to replace the entire rear axle with a more modern one for better brakes and gear ratio. I plan to keep the rest of the drivetrain as is. 235 w/4-speed trans. Has someone done this and can tell me what to look for in the junkyard?

Rob - You've already asked this question and gotten a couple of replies. Please stick with posting in your existing thread as you asking the same question again in someone else's thread is considered rude as it hi-jacks their topic.

gdads51 nothing gets past you 🤣