hey everyone. i have progressed a little bit since my last post. i disconnected the computer in my 81 . i put a demon carb on the motor and a msd ignition. so now i have lost my loc up in my tranny which was the plan anyway but because this car had the th350c i cant just throw a different high stall in it. i am going to more than likely buy a new th350 so i can go to a 2500-3000 stall. what is the 200r4 that everyone seems to be using over there?? is it the same dimensions as a th350? why is it so popular? any pro,s and cons?

 

The 200r4 is an overdrive unit and a near bolt in replacement for a 350. Some feel it is more reliable than the 700r4 overdrive. If you are changing the trans, I suggest you check it out. I decided to go with the 700r4 because of the lower first gear and my 3.08 rear gear. I had to mod the crossmember and shorten the drive shaft.

 

For an 81 you will need to modify or replace the crossmember to put in a 2004R, it also needs a small mod to the shifter and addition of a TV cable. That said it is a near bolt in. Bowtieoverdrives has the bolt in crossmember, I made mine. Since you deleted the CCC you will need to do some minor electrical to get the lockup to work, but its not hard.
I built my tranny from an inexpensive core and have about $700 or so in it with a 2200 conveter.
Should be good to go

 

thanks for your info six footer and kevinator. as im in australia i have never heard of the 200-4R before so im thinking they are possibly not very available over here (although i will find out )but the th350 is ! i think a th350c and th350 would be a straight swap without changing cross members or shortening drive shafts so i will probably head in that direction for now unless someone else sheds more light on it.i dont really need a loc up converter or want one as its only a weekend thrasher.

 

Hi,
I fitted a BTO th200-4r in my '81. I had it shipped from the US at a very good price. Fitted right in with just a custom x-member required. If you're just using the car as a weekend thrasher then you probably wouldn't gain much from an OD trans, but if you ever do road trips up/down the coast then it would be excellent.
Hooking up the th350c locking converter without the computer in place is easy. If you want to do it, give me a shout & I'll tell you what wires need swapping around. It's a simple job & I've done pretty much the same to get the converter locking in my OD trans.
It might be worth seeing what trans are used in Holdens as you may find that you can get a modern GM OD trans for a few bucks at a scrappy (just had an Aussie mate staying with me & every time he looked at the Vette he'd point out all the parts that were common with Holdens, so you could find that 200-r4s & 700-r4s are as common as Roo s**t).

Why can't you just throw a higher stall converter in the th350c? Are none available? I never looked at available converters as I wanted to swap the entire thing out for an OD trans, but is it possible to get a higher stall converter for a "normal" th350 & just chuck it in there? Obviously you won't get the lockup funtion but, apart from that, is there any other reason that a th350 converter won't work in a Th350c (with no computer hooked up, the trans is never going to try to lock the converter anyway)? (Obviously!) I haven't a clue about the compatability of th350 & th350C converters (if you ignore the lockup feature), but I do know that my th350c ran without the lockup enabled & didn't have any problems due to it.

p.s. can't think of any cons with the th200-4r, apart from the cost. But as you're talking about buying a new th350 anyway..... The lower 1st gear ratio, combined with a 2200 stall converter, gives much better off the line acceleration than the stock trans & converter did. Sometimes it even chirps the tyres

 

hey thanks ukpaul for that info. the only converter i would ever use is a B&m and the converters will not fit in a 350C without some modification but then it becomes bit of a weak point.alot off workshops over here make them for a 350c and claim them to be strong but they all blow up !! im looking at over the 420 hp mark now with mods i have done . when i went on the b&m website and flicked through all the catalogue and the holeshot series after all the parts numbers it noted...( will not fit 350C) so that blew that idea.

 

in 1982 700r4 was stock .if you can find a donor car ,that would be the easy way.700 or 200 ?both are good ,both can be made to do the job.

 

No problem. Shame the Th350C converters can't handle the power. Just out of interest, do you know what types of trans are fitted in Holdens?