700R4 in a C3

[matchframe]

I am restoring a 78 vette and am considering replacing the Turbo-350 with a 700R4. What modifications will I need to do to accomplish this? Where is the best place to buy one? The engine I am building, I am shooting for approx. 400 HP. The rear end right now has a 3.08 gear. I am building this car for weekend fun, not really competition or daily driver.

Bill Overton

 

[L82Shark75]

Check out 700R4.com they seem to know what their talking about. They also have a C# intallation kit. I'm kinda in the same boat. I have a TH400 on my 75 vette and I have two options. Change it to manual or beef up the TH400. You should find that site useful. Good Luck!!

 

[page62]

The 700r4 is a good choice with a 3.08 rear. In addition to the tranny and accessories, you'll need a replacement crossmember and yoke. You'll also need to cut the driveshaft.

Or you can go with the 200-4r. It uses the stock crossmember and yoke. And the driveshaft fits perfectly.

Finally, if you do either conversion, I strongly recommend the TV Made EZ system. I tried to do it without this, and it was a nightmare.

Finally, send the folks at Bowtie Overdrives an email. They'll reply with a long, detailed response listed exactly what you need and how many $$$ (including freight!)

 

[Scott81]

Here's my 700r4 installation Tranny Swap I think if I had to do it again I might go the 200r4 route, might be a little cheaper and the plus is that you can use the stock crossmember and driveshaft.

Note: if you are going to use a motor with more HP do not bother with the painless wiring kit, it works fine for stock motors but the vacuum switch doesn't like big cams so go with the 700r4 harness for the lock-up.

 

[crebo]

77 vette 402 BB with 700r4

I had a Bow tie overdrive install a level 2 trans. Works fine for me. I have the stock 3.08. My rpms drop on the highway.........2200rpms... I'm roughly 80 mph maybe 82.
I had to change my crossmember..Get a wiring harness, shave my driveshaft. Spacer for my carb to compensate for the modified bracket and some other misc. hardware.
All in all it runs pretty good until the rpms lower. I plan to let them check it out (warranty). What happens is when its in overdrive and you slow down to about 50-60 (rpms 1200-1500) it gets kinda jerky like it's fighting the lop or idle. I shift it to 3rd drives like a champ pick up alittle speed and drop it back to OD.
I will def. change my gearing though 3.70 or better.
Ashman

 

[page62]

Don't feel badly, crebo. My Bowtie 200-4r does the same thing. It will only downshift out of 4th if you press the throttle. If you're just slowing down it stays in 4th. I just downshift manually, and generally I drive around town with the shifter in 3rd.

I think it's the lack of computer control, speed sensor, etc. that causes this.

 

[mmvette80]

I did the 700R4 swap in the spring. I ordered it from 700R4.com. I have no problems. It cost $1900 for everything(parts). I drive the heck out of my car. If my car was for weekend fun I wouldnt have done it. I would have concentrated on the engine more. I did the swap for cruising.


crebo-
I get that same jerking feeling when the car is in OD and the idle is at 1100rpms.

 

[Scott81]

Are you guys driving at speeds 55mph and below in 4th? If so that's a no-no with the 200/700r4 trans, 4th gear should only be used at 55mph and up as lower speeds are hard on the tranny and that lugging is not good. I have a gas pig of a motor but once on the highway in 4th I get surprisingly good mileage so to me it was a good investment, also have a 3:54 rear.

 

[page62]

Oh no...absolutely not. But in my car it seems like the tranny is a "manu-matic." I have to put it in 4th when getting on the freeway, and shifting to 3rd when I get off...