The thread total is so long, it probably says it all. Recently I weighed my options and talk to some people about how to get the RPMs down in my 1930 Model A. The consensus was that a 49 inch outback would be the best of the options I had. It currently has an old Dana 41. If it had parallel leaf springs it makes perfect sense how to get it all set up by bolting and then welding it in place. This one has the rear transverse spring behind the rear axle so it uses a spring mount system like the SoCal speed shop product to be low. Does anyone have a video, or some kind of step-by-step explanation that shows how you set up a rear in this manner, is it just a matter of making sure of that the spring perch sleeves on the end of these things are straight while the body is on a jack or jackstands and just welding everything where are you want it to stay?
If the current axle has perfect alignment and pinion angle, I would set it on the workbench and replicate all the bracketry on the new axle. Set them up right next to each other.
Based on these three ***umptions: 1- the car currently runs and drives fine with no vibrations, you just need a rear end for which more gear ratio choices are available. 2- The current rear end has correctly designed control arms (traction bars). 3- You have a good welding machine and fab skills. You could do what I did and make a jig off of the old rear end using .120” wall, 2” square tubing - a big T shaped thing with registers for each axle tube, the pinion (this one may need to adjust a little), the two spring mounts and the traction bar brackets. I took the ‘64 Chevelle rear end out of my roadster, built a jig, made new brackets and welded it all onto a narrowed Olds rear end. It bolted back into the frame perfectly.
I was thinking that- put them side by side. I really don’t have the faith in my measuring or fabrication skills…I can stick metal together bit it will be ugly and I may never trust it for something so important.
It’s good that you acknowledge your capabilities as far as welding and fabrication, you don’t want questionable welding on any ch***is components. It sounds like you will need to find a competent shop or enlist the help of a local hot rodder or friend. Good luck.
There should be a few shops that can help you with this. I have not lived out that way in almost 25-years, so I cannot say with any ***urance. If you are stuck, and cannot find anyone to help, look up flights from SFO to BDL. I have a place to stay there, and can feed myself. It would be just flight and labor.
Why don't you just change the ring & pinion in the Dana axle to get the rpm's down at speed? With all the cars & Jeeps that used that axle surely there are gear ratios availabe for it that will do what you need.
It is a Dana 41. They are largely orphaned. They were replaced by OEM's by the Dana 44, which is still in production today. "All the" cars and Jeeps that use them mostly have moved on to something else.
For a guy who doesnt do fabrication ,and welding you may be ahead to change transmissions.We dont know what your running now,but there are overdrives offered in both manual,and automatic transmissions that would largely be bolt in,and give you a better highway gear.
Gimpy- thanks for the offer. That's generous- I think I found a local guy...I also have a tiny garage that would be MISERABLE to work in... I had it narrowed down to 3 options...I forgot that the others were in a different thread. 1. New ******- I was thinking a T5 but really not thrilled about the reviews I see- they seem to be about 50/50 on whether they can handle any amount of hard use or not. Down side would be having to find the trans, shifter, adapter, new driveshaft, new hole in the floor. Thought about a T85 with OD, but not sure where I'd even find one. 2. You can still get ring and pinion gear sets for the Dana 41 but as Gimpy stated, they're not really that plentiful. The shop I spoke with here locally (Chuck's Trucks, recommended in another thread) said that he could put in a 3.54 gear set but said that it's time consuming because it's a lot of trial and error to get the shims correct. He also said that if anything else goes wrong with it, then you're looking for parts that may be hard to find. Mine also has some weepy plug welds...it's also probably 75 years old. 3. Swap to a 9". I presented these options to this guy at Chuck's Trucks and he said that if it was HIS money, he'd do the 9" swap because parts are so plentiful and you could have different third members if you wanted a gear swap. He also reinforced my thoughts about this 3 speed Toploader (1960s era) is tougher than the T5 and already in place and working...seemed logical to update the rear to a 9. He also welcomed me to come in and help him and to learn from him if I do decide to have him do the work. That's unheard of.
The 9" is king for good reason, but do you really need it? It's also a heavy axle, that means a lot of unsprung weight. Does your A really need it? I would say the T5 trans, particularly the World Cl*** version, can handle the torque that the Dana 41 will handle, should be a good match. What engine does your Model A have in it and how much torque is it putting out? You got a big block in that bad boy, or a mild small block? And what rear tires are you running? If the tires don't hook up, that relieves a lot of load from the transmission and the rear end. There are a lot of hot rods are running the T5 we don't see a lot of threads here about them failing. A lot of OT pony cars run them too. If you just want a 9" that's cool, go for it. Just because you want it is good enough reason to do it. But let's not play games justifying it.
Starting on page 16 of my 39 Build thread, there is step by step instruction on how to make a jig for spring perch and ladder bar location and install of another rear for doing exactly what you want to do. give it a look. The jig is very simple to make and can be adapted to an A, 32-34 or like mine 37 up transverse rear spring. https://www.jalopyjournal.com/forum/threads/bringing-my-39-back-to-life.1018747/page-16
Thanks Jason...How did you know that your "welded tubing stack" was the same as your spring? Measurements while the spring had body weight on it? Came out great. The white paint is a nice touch.
yes I measured everything with the car on stands on the axles before I took it all apart and made the spring jig to mimic the spring under load. Worked perfect and will let me set up just about anything with a 40 rear spring.
The Jalopy Journal
