actually i plan a swap from closed to open drivline by my 1/2ton, 1946 but i have an idea and saw this by F**D and the pumpkin rear end. They hold the original rear end and took an U-Joint for open driveline on it. IIRC i saw this for a Chevy rear end at the internet but can't remember the website. I've the R/P 3.55 from Patricks and would like to hold it. Have anyone heard from this kind of rear end swap??? I think weld on a new bracket between rear leafs and rear axle to hold it in position and mounting a U-Joint on the input shaft from the rear end have to be possible. Or Not??
Volker, when it comes to swapping the back end to open, sky's the limit. As long as mounting surface to mounting surface (The back side of the wheel to the back side of the other wheel) is darn near the same, then all you need to figure out is the gear ratio you want. This is important, because the size tires you want to use will help dictate the ratio. On one of my 'puters is a site that you can plug this info in, and it will tell you what the RPMs will be at what MPH you are looking for. Let me know if you want this site and I'd be happy to find it for you. All the best.
http://www.corral.net/tech/gearcalc.html I think thats what you mean I calculate with my 3.55 rear end and found out thats fast enough. theoretical i can drive 111 mph with 215/75/15, 3.55 rear end, 0.7 OD. Wow what a speed, but for that i have to swap my driveline and this is the important thing. I have took a lot of money to rebuild my complete rear axle and now i have to swap ? Not a good idea therefore i'm looking for an solution to hold my original ring/pinion and put a U-Joint on the input shaft of the rear end and use an open driveline. I found a description but he swapped the center section of the rear axle http://www.stovebolt.com/techtips/tranny/bonds/index.html
i talked with my mechanic today and we will do following to swap from closed to open driveline next month. Hold all original parts at the rear axle and cut the torque tube in the middle, put a new seal in the tube and screw an universal Yoke at the open end. Install a crossmember to hold the old torque tube in position and moveable. Then we install the Saginaw 3-speed with OD, take an modern open driveshaft, cut to length and hope it fits between the tranny output and the old torque tube. I was surprised that my mechanic said thats an easy solution for my problem. Will see and come back with few pics.
I don't know about cutting the torque tube at the midway point. It was designed to swing in an arc that wouldn't cause any type of bind to the springs or shackles and may not do so if shortened but it's something I'd explore. If your going open with the driveshaft why not just weld the spring saddles to the axle tubes and make a complete open type rear end. The springs themselves on 55.1 and newer pickups prevent spring wind up and hold the rear in position. I don't know of one for a Chevy but Speedway offers an open conversion for the Ford torque tube rear and I'd bet someone on the H.A.M.B would post a close up view of one installed in their car. It would at least give your very tallented mechanic a few ideas.
I would cut the tube near the axle, put the yoke close to the pumkin and run a full length driveshaft. Make it more like a modern setup.
