Iv heard of putting the 700r4 tailshaft onto the th350 to make the swap alot easyer, so u can use the same torque arm mount, driveshaft and speedo gears. my question is how do you do it? can you just take the tailshaft off the 700r and bolt it onto the 350? do you need a conversion kit? please let me know.

 

ive read a lot of posts about this kit but no one will tell where they got them. must be a secret.

 

http://www.bulkpart.com/cgi-bin/miva...y_Code=Teckpak

 

whenever i did the swap i just got a th350 with the long tailshaft...9". drive shaft fits perfect...only thing if you have an electric speedo you have to get a new mechanical speedo. and the speedo gears aren't really a big deal, there are websites that do the calculations for you on what gears you need depending on what gears are in the rear.

 

I just got a conversion kit. That fits on the existing cover and the gears drive an electrical sending unit that makes your speedo work. I have an adjustable speedo though.

 

Here is the speedo. I decided that when I needed the conversion rather than running a cable driven speedo all the way through the dash that this one was for me. See I don't even need to go to the track..........this speedo tells me 1/4 mi, 0-60 mph, and top speed. It also can be calibrated for rear end changes, tire changes, and speedo gear changes. I love it, makes life a lot easier inside the car.

 

Loos like a Nordskog gauge...how do you like it? I was thinking of going full digital and dumping the 90-92 dash...

Tom

 

LOVE IT!!!!!!!! Eliminates the constant trips to the track (which are great) but when can you do FULL adjustments at the track and then go run..........make more adjustments and then run again, etc. I love it especially the 0-60 time feature and being able to calibrate for tire size changes and rear-end changes too.

 

It can't account for traction loss when calculating your ET

 

B&M make a spacer plate the will go between the end of the turbo 350 housing and the 700r4 tailshaft to mount up and you can use the original brackets on the tailshaft to use the stock torque arm mount. This aluminum spacer is about $150 and I think Summit or Jegs should have it.

 

Holy cow guys, i did this on my 85 vette and it was simple. You have to have a long tail turbo 350 and just use a spacer kit that comes with everything, it even tells you how and where to mount your original speedo gear.

I bought mine from DDW transmissions 574-257-9456. Tell them Mike with the vette referred you and they'll be $75.

I have a cyberdyne digital gauge too, and it gives 1/4, 0-60 etc and can be used for tuning or adjusting to see for changes, but it's not very accurate for actual times. I did use mine to tune in the vac secondary.

Mike

 

What'll be $75?

 

I'd say that kit that allows you to install the 700R4 tailshaft into the TH350 is the best way to go, especially if your TH350 is the short tail version. Try a search for it. That kit will allow you to re-use the 700R4 driveshaft, and retain all the OEM torque arm mounts and brackets. If you happen to have the long tail version TH350 (like I did) then the stock 700R4 driveshaft will work without any type of tailshaft conversion. To solve the torque arm mount issue you can either get one of the conversion kits (B&M, Hurst, etc), or you can convert to an aftermarket torque arm that mounts to the chassis. Be aware that if you go the conversion kit route (B&M or Hurst, etc) your new conversion bracket might not work perfectly with your OEM Torque Arm clamshell brackets. GM used 3 different styles of Torque Arm clamshell brackets over the years, and its possible they wont match up. I had to modify mine to fit, which basically involved drilling out your own holes. The stock 700R4 crossmember probably wont work. I've read that the earlier 200R4 crossmembers from 82-84 cars works great. And I've also ready that the Hurst Torque Arm conversion kit comes with brackets that will allow you to use the stock 700R4 crossmemeber, though my Hurst kit didnt come with them (bastards). I ended up getting a Spohn crossmember (well built but kinda expensive solution). I know this is gonna sound silly, but the hardest part for me was getting the dipstick tube to fit properly. The ones you can buy for TH350's just arent bent right for our engine and firewall (or maybe I got the wrong one).

 

CrazyHawaiian...what did you do to fix your speedo? I got a TH350 with the longtail and the Spohn TQ Arm kit. Only problem I have is that I have no speedo or odometer.

 

I installed my TH350 in my 89 IROC-Z with a cable driven speedo, so it just hooked up and worked. The speed dosnt read right, but that can easily be fixed by recalibrating the speedo gear. Since you have a Speed Density TPI, your speedo is electronic (VSS). I'm not 100 % certain, but I think there is a conversion box out there that will convert the cable driven speedo plug on the TH350 to VSS output. I think it was called a JCI VSS Buffer or something, a device people doing V8 Jaguar swaps need to run cable driven GM transmissions in their Jaguars with VSS speedos. Not sure where you can get them from, I think its like $80 or something. ANother option is replacing your current 90-92 guage cluster with Autometer guages fitted in a custom plate (cpl guys on the boards here have done this).