The plan since the begining 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 horespower 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 crossmember . 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 crossmember 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 crossmember and bolted the 700r4 in. I need to make some clearance at the servo and the case hits the crossmember on the passenger side. I'm going to cut the crossmember off more, to make it possible to get the govenor out, but I left it for a guide untill I weld in more support.
I got the frame connectors welded in, made a transmission crossmember, 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 driveshaft. I think it was easier to put the V8 in the Fiero.
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 crossmember 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.
74 Duster