400 Turbo to 700R install

[csfields]

Looking for information on going from my 400 Turbo with electronic kickdown to a 700R. I am running 3:73 gears and really wanting that higher gear for interstate driving. Needing parts suppliers, how to's etc. Wasn't sure of past threads on here that could help. Not wanting to do a switch either to lock up converter. Any input would be appreciated.

[wbc409]

If you currently don't have a good throttle linkage bracket that has the correct mount for the detent cable, you should buy one. They ensure that you have correct angle and length of travel on the cable. You will need to purchase the correct attaching stud for your carb as well.

If you pull heavy trailers with this truck the th400 is a much better transmission, and there are other overdrive options available.

[Mikem_72]

Check out my build page, post 25, I swapped to 700r4 from TH350. I used the TCI lockup kit from Jegs that runs under vacuum so I didn't have to use a switch and I had to purchase an adapter for my carb throttle. The adapter I got was for a Holley carb and I know there were two different types either for Holley or Edelbrock so purchase for which ever you have. Also my TH350 was a long tail so I had to have my Driveshaft shortened. As far as installation goes it was straight forward it bolted up the same I just had to move my cross member back a couple inches. It was well worth it for me just to be running at lower RPM's at highway speeds.

[Howitzer]

I did this swap on my BBC truck when i tore it down to the frame.

www.bowtieoverdrives.com

I purchased the crossmember, which has a new parking brake lever hook up position, and the TV-MADE-EZ kit, which was machined correctly for my carb. Their website has a few links that aren't the greatest, but you'll manage to get through it. If you're going from VSS to cable speedo i ordered ATP-Y803, and it was the correct length.

Use a tire height calculator and find a website with the correct drive/driven gears for your setup. Take the tail off the transmission and put the gears in.

As far as shifting is concerned, i tried both the Lokar linkage kit and the cable kit. I found the cable kit ACA-1804 to be much more adjustable, i also purchased the back up-reverse light kit to use as the Neutral Safety switch and kept the reverse lights on the column safety switch.

The throttle cable (i have a '72) was also purchased from them as the universal cable, as the cable i ordered from the big thick catalogue of crap supplier (i'm sure you know who that is) didn't fit worth a darn, and i have an Edelbrock carb. I used the universal cable and the one that didn't work and built a hybrid unit that had the look of the original and adjustability of the universal with the correct ends.

I also put the Torque converter electric lock up in my truck, which kicks off when the brakes are applied. You could order this and install it in the transmission and leave it disconnected, and then if you ever want it, it would be very easy to hook up.

[csfields]

Originally Posted by Mikem_72

Check out my build page, post 25, I swapped to 700r4 from TH350. I used the TCI lockup kit from Jegs that runs under vacuum so I didn't have to use a switch and I had to purchase an adapter for my carb throttle. The adapter I got was for a Holley carb and I know there were two different types either for Holley or Edelbrock so purchase for which ever you have. Also my TH350 was a long tail so I had to have my Driveshaft shortened. As far as installation goes it was straight forward it bolted up the same I just had to move my cross member back a couple inches. It was well worth it for me just to be running at lower RPM's at highway speeds.

I am running a Holley Street Avenger with Lokar throttle cable, etc. What gears are you running and what does the RPM drop to in top gear on interstate.

[davischevy]

Pretty much everything I could say has been said.

We are taking another one in this week for the Turbo 400 to 700R4 swap. Luckily we have a guy that builds our 700r's and installs them.

You will love it. I have a 700R4 in my BB Longhorn with 3.73 gears and it works great. Now I can run with any traffic on the Interstate.

The lower low works good when towing also.

[hdff]

Originally Posted by davischevy

Pretty much everything I could say has been said.

We are taking another one in this week for the Turbo 400 to 700R4 swap. Luckily we have a guy that builds our 700r's and installs them.

You will love it. I have a 700R4 in my BB Longhorn with 3.73 gears and it works great. Now I can run with any traffic on the Interstate.

The lower low works good when towing also.

you wouldn't happen to know what number of teeth are on your drive and driven gear on the speedo cable. I have a 700 in mine and I changed the gear from a 3.08 to a 3.73 and now my speedo is about 1o mph fast... need to figure out which one to go to to get it right..

[davischevy]

What's your tire size?

[Mikem_72]

Originally Posted by csfields

I am running a Holley Street Avenger with Lokar throttle cable, etc. What gears are you running and what does the RPM drop to in top gear on interstate.

I'm still running the stock 3.08 gears, it does lag a little off the line and I plan on swapping to 3.73 soon but at around 70 MPH my RPM's are around 2600 to 2650 with a 28" tire height. Im running 15" steelies with a 225/75 tire.

[davischevy]

This will let you calculate speedometer gears.

http://www.tciauto.com/tc/speedometer-gear-calculator

[hdff]

Originally Posted by davischevy

What's your tire size?

255/70/15 and planning on on 275/60/15 in the near future

[71meangreenc10]

You will need a new yoke for the driveshaft, 400's are bigger. I used PATC to get all the parts for the speedometer. Since you are running 3.73's they should have both gears you need. They have the calculator on their site also.

If you are going to tow, I suggest adding in another trans cooler in addition to the one in the radiator.

The lock up is up to you, I added a switch and also used the correct brake light switch.

I am running 3.42 and 275-60-15's.

Shoot me a PM if you need any further info.

https://transmissioncenter.net/

Smitty