I thought that i should make this post due to having to search through countless other posts and i thought i would lay it all out for any one who was interested and hopefully it becomes a sticky or tech article for people who are looking for this info.

You have 3 options in doing this swap and two different kits

First is doing swap with a Th350 6" tailshaft or shortshaft transmission. For this you will need to get a spacer kit that will provide a spacer that goes between the main of the trans housing and the tailshaft. now with this kit it enables you to use the stock 700r4 tailshaft instead of the th350 one. this is good due to it will allow you to use the same speedo gears and hardwear already in the car as well as your tranny mount will remain the same and you will be able to use your stock 700r4 driveshaft. Here is the link to this product and u can find a supplier in your area using the link in the page.Teckpak Swap Kit

Second options is to use a th350 short shaft or 6" tailshaft tranny and get a new transmission crossmember from Spohn which will also give you a mounting spot for your torque arm or you could get a swap kit from B&M or Hurst which will allow you to mount your torque arm to the Th350 tailshaft. For both methods you will have to use a 200c driveshaft out of a 82-83 f body.

Third is to get a th350 Longshaft(9" tailshaft) tranny. For this you will need to either get the Hurst or B&M torque arm mount as well i have heard of people being able to retain there original crossmember and mount for this swap as well with this method the 700r4 drive shaft will be able to be used. altho you will have to modify the speedo gears or speedo its self to either mechanical or electrical or vise versa depending on tranny.

With the Second and Third method the speedo might have to be modified from or to mechanical from electrical as well you will have to purchase a adjustable detend cable which can be found at DETENT CABLE LINK also you will have to get a flexible dipstick found at either Jegs or Summitracing part #LOK-TD-3350400FM

In My opinion option one is the best and easiest swap method with less mods needed

Hope this helped any one who is thinking of doing this swap and this will most likely make it so you don't have to go searching around like a chicken with its head cut off

 

I am getting ready to do this swap and had heard about a spacer that could be used so that the stock driveshaft would fit. But had never come up with anything solid. I for one appreciate this info. Very nice work man. Thanks a bunch from me anyway.

 

where can i buy the kit from b&m or hurst that will allow me to bolt the torque arm to my 350 transmission?

 

you can find this at jegs or summitracing here are the links

B&M swap kit

Hurst Swap Kit

 

Thanks for your timely article - I just logged on specifically to do a search on this topic as I am presently considering my options for a similar swap

What I am interested in is whether there is any feedback on the results of the tech swap kit in drag racing use applications??

I have gone full racing with my 85 berlinetta - and am about to buy a TCI full competition 6in.t/shaft TH350

I will contact tech swap people direct to heare their comments

Thanks for all the help anyways

 

Since the first post is a little vague on the kit, I will add my experience with it. The kit comes with a spacer block, kickdown cable, dustcover, dipstick tube, output shaft, and all hardware needed. YOu install a 700r4 output shaft (from kit) into your th350. Then you install the spacer and finally your tailshaft from your 700r4. This allows all the speedo equipment to remain stock and everything bolt right in. IMO its definately the best way to correct the issue.

 

Sorry I forgot to post the link to the kit. Unfortunately I cant edit, either. Here ya go guys

http://www.bulkpart.com/Merchant2/me...ore_Code=MDITP

 

altho good info sorry to burst your bubble but bulk parts is far more expensive then getting it through one of their direct suppliers which is found in there web site that i posted cheaper is always better but yet again good info thanks

 

You are definately not bursting my bubble over anything. I didnt buy mine from them either. I purchased mine from a local shop. I also wouldnt necessarily say cheaper is better.

 

I did it the 3rd way with my 89 IROC-Z, but I was not able to re-use my 700R4 crossmember. I've read that you can reuse the 200R4 crossmember, but have no experience with that. The 700R4 driveshaft did work good. I bought a Spohn crossmember and Hurst TQ Arm kit. I think something that should be mentioned about the B&M and Hurst Kits is the TQ Arm bushing mounts. Apparently there are 3 different versions of the TQ Arm Bushing (the clamshell bracket that attaches the torque arm to the tail of the transmission). Its very possible that you have a different bracket style than those B&M or Hurst kits are designed for. So expect the possibility of having to drill your own holes to make them work. Not really a big deal, but can **** you off if you expected it to be a bolt on and go type of deal (which was my impression). Another thing that should be mentioned is the vaccum lines. There are a bunch of sources for vaccum, the one I used was right next to the distributor cap. The hurst kit came with a T-Bracket that I used to splice in the vaccum line for the TH350.

Other than that, all I can say is the TH350 kicks ***.

 

I just picked up my th350 today. Got a good deal on it. Fully rebuilt for $550. Told the guy what I was planning on doing, and he told me I needed to keep my tailhousing and get the spacer block for use with the long tailshaft. Now, maybe I moved too soon, but am I going to have to take this tranny apart to swap things over to get my speedo to work? The spacer block looks like it might move things out so that my speedo won't hook up where it needs to go. Am I wrong? This would be the third option.

 

Holy thread resurrection!

This actually answered some questions I had though as I'm thinking of going the 700r4 to th350 route.

 

good info!