Installing the GM 700R4 transmission.
The plan since the beginning for this car was to have an overdrive transmission. After searching for an A500 for quite a while I got discouraged. The car runs pretty good, but the last time I checked, it got 10.5 mpg. I was going to just give up, and get rid of it and get something that gets better mileage, like A 30 FOOT MOTORHOME!! I still can't believe this thing burns so much gas. Several people have told me that Chrysler products just burn more gas. I don't buy it. There has to be a reason. I have tried 3 different carbs with no change in mpg, I have a Thermoquad on it now. The transmission is the only thing that I have not changed. I have a 727 with lockup, I read somewhere that it takes 40 horsepower to turn a 727. I have decided to use an adapter and a GM transmission. Here is a picture of the 700r4 that will eventually go in it. I got it from a salvage yard for 75$. The 3-4 clutches are burnt up but everything else looks good. I changed an 81 Camaro from a turbo 350 to a 700r4 once, and gained 4 mpg. I hope to gain more on this swap, we'll see.
Here's the adapter kit from Wilcap Co. It looks like a well made adapter, but it wont work with TTI headers. They moved the starter location down a little more than an inch. That would have been fine except, the engineers at TTI used that space between the starter and the steering linkage for a tube. A smart person would probably just give up at this point, reinstall the 727 and sell the kit, but I just can't stand it. I bolted the adapter plate to the 727 to find the original location of the starter, then I bolted it to the 700r4. It looks like just a little grinding should give me the clearance that I need. I have access to a milling machine so I can find the location of the starter bolt holes correctly, and mill the starter hole.
The other problem is the cross-member . The torsion bars connect to it, so when I cut it I will have to reinforce it. The best measurements I have made so far are telling me that everything from the inner cross-member bolts up must go.
I drilled the holes for the starter and milled the opening. I was expecting to have to grind for clearance on the trans, but it bolts right up. I guess the starter location was moved for clearance on a different trans. I cut the cross-member and bolted the 700r4 in. I need to make some clearance at the servo and the case hits the cross-member on the passenger side. I'm going to cut the cross-member off more, to make it possible to get the governor out, but I left it for a guide until I weld in more support.
Here is my home made frame connectors. I made them from 2x3x1/8 mild steel. They are cut on the ends to slip over the rear sub frame, and the plate on the front is to weld to the same cross-member that I cut. Also pictured is a bracket for the trans detent and throttle cable. I had a little fun with the cnc milling machine on it.
I got the frame connectors welded in, made a transmission cross-member, and made a shifter mount. The shifter mount is welded to the frame piece that I cut to make room for the trans. It should be a lot stronger than it was. The shift cable is hooked up too. All that I have left to do is the cooler lines, running some wires, and cutting the drive-shaft.
I've been driving the Duster for a while with the 700r4 in it . It has a much better launch now, and the rpm drop on the highway makes it a whole lot quieter. The gas mileage went from a little over 10, to a little less than 15. I wanted to get 60 mpg and run 11's in the quarter, but I guess almost 5 mpg increase is pretty good. I don't know if I would recommend this swap to others, I don't know how hard it is to install an a500.
The cross-member has to be cut and a new one fabricated, either way,and that was the hardest part. With an a500 you can use the stock shifter, and throttle linkage, but I like the B&M shifter. 700r4s are cheaper and more plentiful too.
With the home made sub-frame connectors in place the car is ALOT more rigid. When cornering the Duster has little to no body roll. I can take most curves twice the normal speed for a car this size.
Page 1) Intro
Page 2) The beginning
Page 3) The build
Page 4) Paint/Decals
Page 5) GM 700R4
Page 6) Updates
Page 7) Car Show
Page 8) My friends cars
Page 9) Random pictures
