[rcrta]

Hey need some info please. Gonna swap my turbo 400 out for a 200 r4. What all has to be changed in order to complete this swap?? Gonna be using a lift at shop on wknd and wanna make damn sure I have everything to complete that wknd. Any help is greatly appreciated. Thanks

[padgett]

700R4 has more torque capacity unless built. Also think you need a different length driveshaft/yoke and 200 & 700 are both electronic transmissions so will need a controller. Many have done it just not me.

[Formulabruce]

Originally Posted by rcrta

Hey need some info please. Gonna swap my turbo 400 out for a 200 r4. What all has to be changed in order to complete this swap?? Gonna be using a lift at shop on wknd and wanna make damn sure I have everything to complete that wknd. Any help is greatly appreciated. Thanks

I did this swap and use it currently in a Bird.
1. You can LEAVE the TH400 Cross member. a tiny bit of grind on the elongated holes for the mount and its shoe in.
2. You will want a TH350, or 3, or 4 speed drive shaft for this, any except a '72 M22 will do fine.
3. You will need a TV cable bracket for the intake.
4. You will need a adjustable TV cable for a 2004R
5. A Th350 shift cable and trans bracket will work with a slight mod to slider for the mounting bolts.
6. Shiftworks has a detent kit for the console shifter. Drill out old and bolt in new.
7. Can use a stock th350 Flex plate. not a TH400 one.
8. If you want lock up you should get a 2004R torque converter
9. I run a external cooler out in front of the radiator and a remote filter as the pan has no drain.
10. When built right these can easily handle up to 450 hp and 500 ft lbs of torque.
11. I got mine from PATC and its a stage 3 raptor, tested on a dynow before shipped.
I run it behind a 455HO and I can assure you that the driveshaft will destruct before the transmission gives up.
12. You should buy one built so it has a hyd shifted valve body, so No controller is needed. This makes it a 1 wire trans ( lock up 12 volts which you can grab at the gas pedal from the TH400 wiring, or put it on a switch)
About 3K will get you a stage 3 unit. The gas saving will pay for it in 3 years if you drive 3-4k miles a year
.67 Over drive is better than a new tremec 5 speed ( .68)
Below is with 3.42 rear gear and not downhill, was a slight incline.

[rcrta]

Mine is built by Janis transmission in Ohio. So a turbo 350 flex plate will bolt to a Pontiac crankshaft?? Gonna replace external cooler with new one. Probably gonna purchase new shifter like what u have or B&M. I was told I could change yoke on driveshaft and mine would work just fine.. 31 spline to a 27. Driveshaft work??

[76TA462]

I replaced my TH400 with an Extreme Automatics Stage 2 2004R early 2020, in my 76 TA. No floor modifications. Used my existing 3-speed B&M shifter which was easily converted to a-4 speed. Same drive shaft with no length change needed (thought I would have needed to size it, but it was a perfect fit as was), and same cross member (just had to use a taller tranny mount to align things). Replaced the yoke with a GM 27 spline. Had to replace the torque converter (also decided on non lock-up for my application. Added a good tranny cooler and fan (Derale 13720) which was highly recommended by tranny company and many others. TV cable and bracket is needed and was supplied with my transmission - and worked great and came with excellent installation instructions to dial it in. Behind a very stout 455 (north 0f 475 foot pounds currently). Been a thrill. Crisp clean shifting, and the overdrive is great. Love it. Rear is 3:23. Absolutely zero problems and its been pushed.

[76TA462]

Meant north of 575 foot pounds.

[76TA462]

Oh yeah, it bolted on directly. Had both the Chevy and BOP style bolt pattern.

[Formulabruce]

Originally Posted by rcrta

Mine is built by Janis transmission in Ohio. So a turbo 350 flex plate will bolt to a Pontiac crankshaft?? Gonna replace external cooler with new one. Probably gonna purchase new shifter like what u have or B&M. I was told I could change yoke on driveshaft and mine would work just fine.. 31 spline to a 27. Driveshaft work??

We are talking Pontiacs here, why wouldn't a Pontiac 350 engine, with a Pontiac th350 bolt together?
Many Pontiacs came with a TH350, which had a th350 flex plate bolted to the crank.
Have to check length on a replaced yoke shaft to be sure.

[giles]

2nd gen Firebirds built after 74 were THM350. The THM400 would not fit along side the catalyst. This is why 75-76 455s were 4-speed only.

[Formulabruce]

While all true, 1970 to 1973 ( mostly with 350 Pontiac engines) Firebirds came with a BOP TH350 transmission.