Hey all,

I love my th-350, and I'm slowly saving up for a built 700r4...but I have a little extra money on hand right now. My Uncle's '71 Cutlass Supreme Convertible has a shift kit, but he doesn't know anything about it. What's the "best" one I can get for my trans? I'm looking for street performance more than anything. I found one on Summit, but I'm not sure if it's well known or recommended. All help is appreciated! Thanks

http://www.summitracing.com/parts/trg-350-3/overview/

Also, is this a Stage 1,2,or 3 kit?

 

I've always done the DIY shift kit or what some call the factory shift kit. If you are replacing it why spend the money. If it's a harder shift you want you can drill out the holes a tad bigger and remove some checkballs. Shim the accumulator or put some spacers in it or some remove the spring totally. Specifics on how to do this are on the web.

A lot of those kits come with all the parts and instructions for a 1,2 and 3 in the kit.

 

Download the instructions for that kit and every other trans company. Read them over. I bet you can do what they tell and it is much cheaper than buying the whole kit.

As above figure out which holes in the plate do which shift. Don't get too wild with the holes as small increases do big changes. I shunned the accumulator with a nut and put a stiffer spring in. Do some google searching , no telling what you can turn up.

 

I used the TransGo kit in your link. It works a bit differently than what the fellas are explaining above in that it also uses different pressure springs to modify the valve application points. I like it and it has served me well for the past 30+ years.

On my Fords with the 4R70W transmission, I did essentially what was said above and enlarged the feed holes in the valve body separator plate, but I was following an instruction manual published by a Ford transmission design engineer for that. I wouldn't know what to do on a TH350, but from my Ford experience I can say it sure did the job.