Planning overdrive trans swap

[Obwonkonobe]

Hi all, ive got a 78 c10 with a 350 350 combo, and the millage is just awful. Over the summer il be on the highway every day and need an overdrive trans or il have to sell the truck. Ive heard that 700r4s are good to swap, i have a 9 inch tail housing. Id like it to be as simple as possible, and il be hunting craigslist for it.

I need to know what to look for to get simplicity. Ive heard 700r4s are a direct swap. And ive heard that a 4l60 is just a renamed 700r4, and a 4l60e is an electronic one. What years should i look for? And what tailhousing will i need for a 2wd. Last thing is if i go with an electronic trans, what will i need just bare bones to make it work, i just need it to **** and show speed, thanks

 

[CSFJ]

You might want to run the numbers on cost/gain. Find out how many mpg's you can realistically expect to see, versus cost of swap.

 

[74 Shortbed]

It's not just the MPG that is a factor, it's wear and tear, heat and irritation, lot nicer to cruise at 2000rpm than 3500rpm..

 

[CSFJ]

It's not just the MPG that is a factor, it's wear and tear, heat and irritation, lot nicer to cruise at 2000rpm than 3500rpm..

Going from 1: to 1:0.74 will drop it 1500rpm?

 

[74 Shortbed]

Going from 1: to 1:0.74 will drop it 1500rpm?

Yep, kinda what I said and that's a lot..

 

[Crispy]

Are you hoping to swap in the 700r4 as bought or are you budgeting a rebuild into the purchase price?
Remember you will need to have your driveshaft shortened or buy a used one from a later model C10 with a 350/700R4 driveline.
The crossmember needs to be moved back a bit to accommodate the mount for the longer 700R4.
You will also need to make sure the TV cable for the 700r4 is installed at the correct angle or youll burn it up.

Its a pretty common swap and tons of info is available. The biggest thing is either sourcing the right tranny or cheapest tranny along with a good rebuild.

EDIT: forgot about the torque converter. If buying used try and snag the torque converter with it. Your TH350 converter wont work.

 

[Obwonkonobe]

Im not all that worried about cost, il sell the th350 that's in right now .It works

Are you hoping to swap in the 700r4 as bought or are you budgeting a rebuild into the purchase price?
Remember you will need to have your driveshaft shortened or buy a used one from a later model C10 with a 350/700R4 driveline.
The crossmember needs to be moved back a bit to accommodate the mount for the longer 700R4.
You will also need to make sure the TV cable for the 700r4 is installed at the correct angle or youll burn it up.

Its a pretty common swap and tons of info is available. The biggest thing is either sourcing the right tranny or cheapest tranny along with a good rebuild.

Im not going to rebuild it unless I kill it, and i ca, modify the crossmember myself. No problem. I can hook the tv cable up alright. Shouldn't the driveshaft work since its a th350 already?

 

[74 Shortbed]

Yep same yoke just have to shorten it.

 

[Obwonkonobe]

forgot about the torque converter. If buying used try and snag the torque converter with it. Your TH350 converter wont work

Yea I will lol, if i go with a late 90s trans do i need a flex plate adapter?

 

[Obwonkonobe]

Yep same yoke just have to shorten it.

Damn, il be breaking out the cutting wheel and welder than lol

 

[74 Shortbed]

Damn, il be breaking out the cutting wheel and welder than lol

Don't forget the balance machine, lol..

 

[Obwonkonobe]

Don't forget the balance machine, lol..

Ugh unfortunately my wallet wont

 

[74 Shortbed]

Ugh unfortunately my wallet wont

Nope, lol.

 

[4WDKC]

Im not all that worried about cost, il sell the th350 that's in right now .It works


Im not going to rebuild it unless I kill it, and i ca, modify the crossmember myself. No problem. I can hook the tv cable up alright. Shouldn't the driveshaft work since its a th350 already?

700r4s are all the same length they just have different tailhousings for different cars Corvette,Fbody,Caprice I believe are all of them. If it were me I would seriously consider going to a 4l80e and not having to mess with when you kill it. Get the ECM from a truck and have it flashed to be a stand alone controller.

 

[Obwonkonobe]

700r4s are all the same length they just have different tailhousings for different cars Corvette,Fbody,Caprice I believe are all of them. If it were me I would seriously consider going to a 4l80e and not having to mess with when you kill it. Get the ECM from a truck and have it flashed to be a stand alone controller.

Do I just give it 12v and plug it into the trans? And what do you mean about killing it?