I need some help!
I talked a friend of mine with a 68 into a power glide to 700R4 swap the other day and I need to know what's necessary to do this and make it look stock (on the inside, console etc.) Also what rear end would work well with the first gear and overdrive ratios of a 700R4. The motor is presently a small block with about 400 Hp. I would like to hear from anybody who has done this swap or knows what parts I'll need.
Shoulda kept my mouth shut!
Thanks
Jim

You'll need a crossmember with the tranny mount about 2" rearward of the stocker, a 3" shorter driveshaft and a method of controlling the lockup of the converter.
The rear gear ratio depends on the rpm range of the motor and your desired performance. You need to be able to operate for extended periods of time at freeway speeds with the converter locked and the engine developing reasonable VE.
There are conversion kits for adapting the PG console to the 700R4. I just used a stock PG column shifter on my 700R4 and it worked very well.

I had to shorten the bell crank on the shifter shaft a hair so the stock shifter could stroke all the gears. If you use the stock bell crank, you won't be able to hit L1.

I can't tell you exactly how much I shortened it but I can tell you how. I stuck a piece of wire in the hole on the bell crank that I could lay up against the bracket for the shifter cable. Then I measured how far the stock bell-crank stroke was from Park to L1. The stock shifter stroke is about 2". I then took the ratio of my measurement to the desired 2". Using a made up example, lets say my stock crank stroked 2.5". So the ratio would be 2/2.5 or 0.8. I then shortened the bell crank by 20% making it 80% of it's original length. To do this, I cut it, overlapped it and welded it back together.

Just be sure to tac it before welding so you can confirm your measurements were correct and that the shift can stoke all the gears.

Thanks for the reply guys.
I just visited shiftworks.com for shifter mods and bowtieoverdrive.com for a crossmember. The converter lockup stuff is still a bit of a mystery at this point but I'm workin on it. I understand the 700R4 has a 3.36 first gear and a .70 overdrive. I'm thinkin a 3.42 or a 3.55 with a 26" tall 255-60-15 should be a hoot to drive?????????????
Jim

Hi Jim,

The 700R4 has a 3.06 first gear, and the 3.55 would be fine. I use a 3.73 with my 2004R, which has a 2.76 first gear, and it's perfect.

The lockup wiring is very simple. "Keyed on" 12V to the lock-up solenoid is all you really need. This will give you automatic lockup in OD. As a safety, I run that wire through a GM cruise control brake light switch GM# 25524848(I think!), so it unlocks when I hit the brakes. The switch is a direct replacemnt.

The shiftworks kit works perfectly, and you can use the stock shifter cable.

Good luck, and
Happy Holidays to you and Linda!

Al

PS FYI - The 2004R is an easier swap! No cutting the driveshaft.

PPS 200 or 700, make sure you understand and set up the TV system properly!!!!

While you're shopping for parts, don't forget a proper hookup for the TV cable

Jim
Shiftworks kit I'm told will include brackets for the TV cable.

Al
Thanks. I understand how the TV works. Is the 200 as strong as the 400? I remember the 200 being a problem tranny? Maybe gettin old? Thanks for the tip on the cruise control switch. Isn't there a vacuum switch in there somewhere too? I don't know at this point if it's necessary but I'm still looking.

Happy holidays and a Happy New Year to you and Paula and everyone on the site
Jim

Originally posted by GMJim:
Jim
Shiftworks kit I'm told will include brackets for the TV cable.

Al
Thanks. I understand how the TV works. Is the 200 as strong as the 400? I remember the 200 being a problem tranny? Maybe gettin old? Thanks for the tip on the cruise control switch. Isn't there a vacuum switch in there somewhere too? I don't know at this point if it's necessary but I'm still looking.

Happy holidays and a Happy New Year to you and Paula and everyone on the site
Jim I'm sure you meant 700 not 400!?!

In stock form from what I've heard it's pretty much a tossup. When you start looking to really beef them up, there are more and better parts out there for the 200. The 200 is an easier swap due to the driveshaft issue, and it has better gear spacing than the 700.

A couple of interesting articles, but not to say this is the final word.


http://www.drwtransmission.com/thm_200-4r.htm

http://www.drwtransmission.com/4L60E.htm

You can run the lockup circuit through a vacuum switch if you want, and many do, but it's not necessary.

Cheers!
Al

Sorry Al
I meant 700 :confused:
Jim