Jakeshoe has a good TH350 buildup at the top of the Trans-Rear section>> http://www.hotrodders.com/forum/th350-rebuild-tech-145361.html
I'd go with the TransGo (350C-1&2) Reprogramming Kit. They're engineered better than the B&M Kits.
http://www.transgo.com/rpg_generalmtr.php
Other TH350 Info>> http://th350.netfirms.com/browser.htm
Shouldn't need many Trans Mods for 300-350HP.

 

ok great thanks. now any suggestions on using the 350 or 350c because i do have both what are the benafits of each i know some of the more extencive rebuild kits you can not get for the 350c. is it worth doing a full rebuld or just work on the valve body???

 

You shouldn't have any problems finding rebuild kits for either Trans. The TH350C's seem to last longer than the regular TH350 trans. Maybe because of the Lockup TC/TorqueConverter allowing the trans to run cooler. The 350C's lockup TC will give you slightly better MPG also as it lowers cruise RPM 150 to 200rpms. While the trans is out you should replace every seal you can get to if it's in good shape. If it's questionable rebuild it. TH350/350C are one of the easiest to build.
Here's a few sites for Trans parts>>>>>>>>>
http://www.makcotransmissionparts.com/350-350C.html
http://www.transmissionpartsusa.com/350_transmission_parts_s/598.htm
http://www.transpartsonline.com/tpfile/tpcat.asp?TransPartsOnline=350&TransPartsType=350
https://www.wittrans.com/Default.aspx?
This tool will be needed>> http://www.transmissionpartsusa.com/TH350_700R4_transmission_tool_p/300-000jt0151.htm

Todd

 

the main differences in rebuild kits for the t-350c trans from a regular t-350 is the valve body gaskets.

Most sealing ring kits had all rings needed.

the variances in the bushings used at the meeting of the input shaft and output shaft is easy to take care of. I use the plastic insert style bushing at this location.

The hard parts failure spot on the t-350c was the internal spring hub for the lock up clutch of the converter. Next problem area was the solenoid.

A t-350c can be run with out the converter clutch engaged , I never seen a over heat problem with a t-350c if the converter clutch was not used.

I have never seen a t-350c last as long as a non lock up t-350 if maintenance was equal. the converter would fail first in the t-350c

 

The TH350C's seem to last longer than the regular TH350 trans. Maybe because of the Lockup TC/TorqueConverter allowing the trans to run cooler.

I'm thinking the longevity that you may have seen, SS64, may due to the "C" tranny being used behind some of the weakest SBC's and 90 degree V6's out there.

I have an un-rebuilt original w/about 100K miles on it (only had fluid and filter maintenance since new) in my '80 Malibu.

It will leak fluid if the car's not driven- usually after about a month or more of sitting- requiring a couple quarts to top it up before being driven. Oddly, I've never actually seen where the fluid is leaking from.

Lock-up and all other functions still work fine.

I might have put a Trans-Go kit in it years ago when I first did the filter the first time or two, but I'm not positive about that. But it has been a model of reliability, for whatever reason- but only dealing w/a 115 HP engine plus good maintenance- it SHOULD have lasted!

 

im runnin my 91 700r4 without the lockup plugged in

and have had many the same way

and never a failure or any issues

mines unplugged now because the lockup started failin and lockin and unlocking over and over down the highway

so..

never any overheating or foamin of fluid or anything

no difference in driving

same way with th350c if clutch was not plugged in

i have a th350c from an 81 c-10 pickup sitting here i need a gas converter for it so i can use it in something, it was behind a diesel oldsmobile 350 so it has 10 bolt universal bellhousing as did most or all of the th350c trannies