I have been putting off my swap do to mixed outside oppinions about the ups and downs of them. I actually built and modified my 1988 700r4
to drop in my 65 impala ss 396, but then purchased my vette shortly after and started thinking of shoving it into my vette instead. Both are using a th-400 now and are in great shape. There is no "real" need for either to change, I just want to do it. The other reason for the change in mind about the impala, is I now have a complete muncie m-22, bell housing, flywheel, clutch linkage and shifter / console for it and will probably go manual with it.

Anyway, what's the best thing you could say about your change, and what is the worst thing about your change? I'd appreciate hearing from those of you who have actually done the swap than all the input I seem to get from people who don't even actually know.

The one thing I seem to have gathered that holds pretty steady accross the board, is don't put a 700r4 behind a deisel.

 

I had the 700 vintage late '87 unit rebuilt locally here, and put it in with a vette converter and shift kit by Superior, with most of the mods, I had to play with the governor to get the upshifts way higher than they were, these things are VERY sensitive to the throttle cable tension adjustment, VERY,

I found that for ME, I was using the lockup active in 2-3-4 gears, and when doing that the shift was really nice and firm, but I suspect it's what cost me the 3/4 clutch pack after about 4 years.....so I put in a tight truck converter, and still now get my pleasant bump/kick in the *** when it shifts, with converter running normally via computer, I have DPFI, so this is not an issue...

GENE

 

The reason I made the switch was I had been running a 350 trans. behind a stock carb. 350 engine in my 66. My car has side exhaust. At 70 MPH I was running 3000 RPM. I could not hear myself think and had a hard time carrying on a conversation with the noise. I switched the carb. engine to a TPI system. I figured since I was pulling the engine why not to advantage of a lower RPM and reduction of the noise. Now at 70 MPH I am running at about 1900 RPM. Less strain on the engine and now I can talk and hear in the car. I increased the torque.
I bought everything from BTO. This let me keep the original shifter so no mods. had to be done to the console, shifter, tunnel.
The only critical thing is the detent cable needs to be properly adjusted for proper shifting. I am running a computer for the TPI but it is not connected to the trans. The wiring for the trans. is only one wire connected to the brake. When in 4th. gear pressing the brake pedal releases the lock up. Wiring is straight forward.

hope this helps,

 

Bobs77, Thanks for your input. I will make the changes this weekend and give it a try.

 

best things...they tie for first place: since i'm running 3.08s is first gear.... next best thing is the OD at highway speeds 65 is like 1700 rpm....

only minor issue is at the bottom end of 4th gear like at the end of one highway ramp getting on another you can slip down to 38MPH at 1100 rpm and still be in lockup and accelerating.....if you push it a little harder it will down shift into third....

 

in reguard to the 3-4 clutches burning out may be to the fact that stock 700r4 have a 3-4 check ball that reduces shift pressure/flow to soften the shifts. remove it!!! it shifts harder but gives you full pressure at shifts and reduces clutch slippage and burning. I actually have a manual on it that shows exactly what to do and some other mods to make. Sadly I mentioned this before and many asked for it, I was just too busy at the time to copy it to a computer format. I will try to post it soon for you all. I know it was an expensive manual, and an equally expensive extra mods manual. I bought them at the time as it was my first 700r4 rebuild. Like everything else, I did it myself, and would only recommend the more experienced or mechanically inclined to try. It isn't really very hard, but it's ALOT of parts as well as several special tools, and can take a bit of time. One other tid-bit of info, is "as far as I know" the 88 and newer 700r4 is what you want, and can be identified by its date code, or by looking at the case where the tranny cooler lines go in, and you will see a large "rainbow" shape cast raised on the housing. These have larger shafts and are heavier duty.

Take care all, and I will try to convert my manuals to .pdf files as soon as I can.

I will add a new post when I do, and probably e-mail it out to those who ask.



Loren

btw: still interested in hearing from those of you who have actually done the swap and what you think. ( good and bad )