700-r4 swap

[rapidride3]

I have a 1976 cheyenne that has a 350c.i. 2 barrell with a th-350 transmission. I would like to convert to a 700-r4 o.d. My question is,,,what do i do about the tv/cable off of the stock 2-barrel linkage???? mwhat are my tv options with the 2-barrel. I really do not want to switch over to a quadrajet or holley 4-barrel for the 700 r4 trans swap BECAUSE i will someday be adding an edelbrock fuel injection system on a built 383 later on. However,,,I was wanting to do the trans swap now.

[Russell]

Hey man!

I did a similar swap with my 77, and had no troubles at all

The 2 barrel carb's current TH350 kickdown is the same for the 700r4. Simply slip the TH350 cable off the carb, and unhook it from the bracket, then slide the TV cable in, and slip it's end over the nub on the carb. You then push the little "D" button on the TV cable, and slide the slider all the way towards the firewall. You then grab the carb linkage by hand, and force it to wide open throttle.

This should cause the TV cable's slider to slip forwards a few notches, and should have the TV cable set properly to within 1 tick of the correct position.

If you get in your truck and drive, and notice that the transmission is shifting in a short, stacked pattern, stop immediately, and slide the TV cable towards the firewall a tick or two.

If the transmission is holding the gear too long, then clunking into the next gear, then your TV pressure is too high, and needs to be moved towards the carb a tick or two.

Keep in mind that a little movement means a lot of change in how the transmission behaves, so making sure you only move it a tick is critical. I usually set mine so that it'll just downshift at 40 mph or so, and generally that is fairly close to where you want it. Also keep in mind that you shouldn't be fidding with the TV cable to make it shift how you want. It isn't designed to work that way, and driving with it out of adjustment too long will damage the transmission, esspecially so if the TV pressure is too low.

With regards to the rest of the swap, it is actually very easy.

The bellhousing and torque converter bolt straight up to the engine, using the same flexplate as the TH350 did. Make sure you get a lockup converter for the 700r4, as it is different from the TH350's converter.

You will need to slide the transmission crossmember back a touch, and drill new holes in the frame for bolting it up, but it uses the same mount as the TH350 does.

The driveshaft for the TH350 is the same length as the one used by a 700r4, as long as the TH350 in your truck is the stock tail length.

You will also need to wire up a controller for the torque converter lockup. It is easiest to get a harness from an 83 - 86 pickup equipped with a 700r4. Then all you need to do to hook it up is change the plug that goes into the fuse box from the new style plug, to a spade type connector & plug it into an ignition source, change the brake light switch over to the one from the donor truck, so you can unlock the converter by hitting the brake, and run a vaccum line from full intake manifold vaccum to the little vaccum switch that you'll bolt to the firewall.

Also make sure that you use a BIG cooler on that transmission, the bigger the better, and never tow anything, not even a box load of stuff in overdrive. The OD bands are only pencil thick, and are easily killed.

If you haven't already, consider getting it rebuilt, and built up to support the power and torque that your 383 will be producing. It is very likely you'll blow it up in short order otherwise.

Hope this helps a bit, and sorry for the total lack of organization in my post, I was just putting down info as I remembered it in my head, LOL

[rapidride3]

Thank you,, I should be alright ,,, I believe i am gonna go with a bowtie overdrives 700-r4. Tey offer 4 levels of power capacity,,, so I should be alright. Don't they sell an aftermarket tc lockup switch??? Thanks for the informative reply. Matt

[Russell]

Yep, they do sell their own aftermarket controller, just ask them about it when you purchase the transmission. Make sure you mention the 383 to them, and get their opinion on what level you want to get.

Bowtie Overdrives is definitely one of the best transmission houses out there

[bluex]

Originally Posted by Russell

Yep, they do sell their own aftermarket controller, just ask them about it when you purchase the transmission. Make sure you mention the 383 to them, and get their opinion on what level you want to get.

Bowtie Overdrives is definitely one of the best transmission houses out there

Bowtie Overdrives is great!! I got everything, but my tranny from them. They have really good customer service and will answer any questions you have. I even called them to verify my pressures and all so I was sure the tranny was setup correctly.

You will be happy with anything you get from them. I have only heard good things about their trannys. If I would have had the $$$ I would have got one from them.

[rapidride3]

Cool that will be who i probably go with.