I want to swap the TH350 auto trans in my Nova for an overdirve automatic trans. I have a stock 350 engine. Which overdirve trans would be the best/easiest one to use? I want to keep the column shifter and the mechanical speedometer.

Thanks
Mike

there is no real easy swap. The 700R4 , 4L60E and 4L80E are the choices and all are expensive to rebuild. You'll need a new drive shaft , you'll need to alter your trans crossmember , you'll have to fab up linkage for the column shifter and you'll need a kit to used the mechanical speedo work.

My choice would be a gear vendors over drive. They are pricey but musch less labor is involded and all you'll need to do is shorten the drive shaft and hook up the switch. I know a guy makin over 1000 hp goin through one of these and he drives it on the street and loves it. He is 70 years old and has a blown and sprayed sbc that goes into the 8's and then he drive it home.

I would recommend the 200R4 as it is the same size overall as the TH350. The transmission cross-member will have to be modified (there are people who sell them pre-fabbed and ready to go online, but you will have to Google it because I have forgotten their URL). The drive shaft may work as is depending upon the front yoke you have now. Tranny cooling lines are a little different in were they bolt up and have Metric fittings, but you can splice into your existing lines the added tube with the correct fittings. The detent for the shifter will bolt up but you will not be able to put it in first gear manually.


Big Dave

Mike, you can get all the parts you need from Bowtie Overdrives- crossmember, TV made EZ kit, install kit, speedo sleeve, speedo gears and inspection cover.

It's not real hard to put a 700r4 in, I had one in my 70 for a while behind a 327 until I decided I wanted a manuel. Here is a quick run down on what I had to do. I took a th400 cross member and cut off the mount and welded it back on the opposite side. The cross member sat back about 1 inch so I had to drill new holes in the frame. A th350 mount will bolt on to a 700 and the yoke is the same as well. The driveshaft had to be shortened about 2 inches. The 700 shares the 350 flywheel bolt holes so weather you have the big or little flywheel it will bolt up(mine had the little 153 tooth).If you get a newer 700 that has an electronic speedo you can use an older output housing that has the mechanical speedo(they interchange). My cooler lines went right in with no problems, leaks. My car was a 3 on the tree so when I got it and changed it to a th350 about 12 years ago then 3 years ago to the 700 so for the shifter I had a B&M so the column shifter I can't help with. But a 72 GMC I converted a few years earlier with a column shift did go all the way into first. I don't know if the Nova will but that truck did and everyone said it wouldn't.
I changed mine back to a stick(4 speed) so I don't have any pics of what it looks like in the car but I can take some of the cross member to give you an idea of what to do, if you decide to go that route.