I decided to convert to a turbo 400 auto. Has anyone else done this? Specifically what do I need and who makes it? I have already decided on the trans and tork converter. Need advice on what flexplate, cross member, safety loop, tork arm, console, shifter, and driveshaft. I will be using a Turbo 400 with an ultra bell housing, full manual valve body, reverse shift pattern, and a 3200 stall converter. I know its heavy and overkill but the trans will hold up for several years and be ok if I ever build a stroker.

 

I am in the process of the swap myself and have all of my parts except for the trans and driveshaft. For the flexplate you can get a Jegs SFI approved one. part # from Jegs is 555-60153 for $59.99. You can use your stock T56 crossmember and elongate the hole 3/4" towards the rear of the mount. You can use a spacer of 1.5" out of aluminum flatbar stacked up with a hole drilled in and a longer bolt but it is not necessary unless you need to raise the tailshaft up to fit a driveshaft loop. To make the speedo work you will need GM part #'s reluctor-8655315 pickup- 8655291 and connector-12085498. I am using a pistol grip hurst quarter stick with an A4 console out of a 2000 camaro but you could use your stock t56 console. There are a variety of shifter that will work. You will need another driveshaft. You can get a driveshaft from denny's driveshaft or madman and co. racing. You will need a tranny dipstick from madmanandco. also. You can get a spohn or similar torque arm with the driveshaft loop already built in. Lastly, you will need a tranny cooler like the B and M part #130-70266 from Jegs. That's about it.
Good Luck
Matt

 

You'll also need a slip yoke for the transmission. The TH400 output shaft has a larger diameter that no other GM tranny yoke will slide onto. You can't use a bolt-on yoke from a truck. There are no factory 1350 series yokes.

If you buy a new yoke then get a 1350 series u-joint style. Then get a new driveshaft with 1350 yoke ends. A 1350 series yoke for the differential can be pulled from Astro vans.

Or you can just keep the small factory u-joints.

A TH400 is around 175 pounds. Not as nice as a 95 pound Powerglide. A TH350 is around 150 pounds. Not sure about an A4 or M6.

UltraBell housing is the way to go. Then you don't need to find a Chev bellhousing TH400. BOP TH400 are easier to find.

A full manual, reverse pattern will suck on the street. Having to manually select gears gets tiring after a while. As long as nobody else drives it, selects D and drives off. Those valve bodies also eliminate engine braking in first and second gear. That's not good in a street car. If in first or second gear and you lift off the gas, the car will act like it's in neutral.

 

That's true in the 400, however TCI makes two different manual valve bodies for the 350 that retain engine braking. One (321000) retains 2nd gear engine braking the other (321001) retains 1st and 2nd gear engine braking. They aren't reverse pattern though.

 

Thanks guys. Got all the info. I just ordered my Turbo 400 from a local shop. Going with a full manual valve body. I really don't drive it on the street that much so I can deal with the stop before downshifting.

 

Why the Ultra Bell? I used to work at JW and didnt really care for them. Unless the design has changed. Also call SFI and see if he ever really got the certification. When I left there he hadent but was putting the sticker on any way.

 

According to my tranny guy its SFI certified. If I later decide to put the stick back in the ultra bell will fit my 69 Judge. The only thing is that you need a 10" converter or smaller.

 

Just a hint if you buy a converter from JW. His are Continentals. I have one. 8" 5000 stall. If I bought another Id' try to go to Continental direct. Mine has held up real well. Dont get me wrong but John can be a little sneeky.

 

I was wondering about the th400 swap too. I dont know really at all what I need. Do you really need a new flexplate. My car is a 93 trans am auto. I plan on a auto valve in the 400. The biggest question I have that I dont think anyone already answered is do I need someone to fabricate a custom crossmember. I think BMR has some th350 ones for my car but I talked to a guy there and they want to come out with one eventually for a 93-97 th400 but they arent going to come otu soon I dont really remember. Is there anyone that can make me one or has soem already. Also I ran across a turbo400 conversion kit at fbodycentral.com I dont know what years it was for. It says it comes wtih a th400 a crossmember and a adapter for ur speedometer. thanks for your help

 

Good luck with the swap Kaz, sounds like you'll be all set to kick some a$$ bracket racing next season. Thanks again for lending me you're skinnies the other week, they did the trick

 

fastlane396, I have the BMR tork arm but have decided to go with a Spohn. $415 includes a cross brace, adjustable tork arm that attaches to the cross brace, and safety loop. Sphon has 2 setups, one for stock exhaust and one for long tube headers. The cross member must have the holes drilled back to fit the longer Turbo 400. Also you need 1.5" spacer. Spohn can make one for $20. Spohn makes an exterme drive shaft ready to bolt in after the conversion for $315.


Gregg, no problem. I did get the wheels back. I forgot that you were returning them. Overall I was disappointed with my last season. I finished 29th overall points which was the middle of the field. Not too bad for my rookie season but I really expected to do better. Hopefully the auto will cure some of my problems. 90% of my losses were due to the stick.

 

OK first of all ( I know this isn't the for sale section but...) I have a SFI approved flexplate for an LT-1 motor. I bought it for my swap, drove the car twice and then took it out cause I am changing motors. This one will not work with my GN motor.

FOR SALE 45$ buyer pays shipping

Ok for my swap I bought:

1 dipstick tube from Madman, I would suggest doing this also.
1 Spohn torque arm
1 Coan TH400 race built reverse patten manual valve body
1 Coan converter
1 Hurst quarter stick
1 Driveshaft form Denny's nitrous ready driveshafts. $240 range I think. Really easy instructions on how to measure for the drive shaft on there website.
1 tranny cooler

Other then that I sloted my hole in the tranny crossmember like menchined above and used a 3/4" spacer.

the rest, you guys have figured out already.

Oh I also bought a pedal ***'y for $15 off the board...

I bypassed my neutral safety, didn't hook up a speedo because it is a drag car, and didn't hook up reverse lights. I don't know about any of that stuff but I am sure it isn't that hard to figure out.

 

JC are you going to get a BOP trany or get the conversion plate for the v6 setup?

Steven

 

Well right now I have the BOP adapter plate and it holds strong.

Later in the year I am sending the tranny back to Coan to get a transbreak put in and I am going to see if they will just switch me casings.

 

Just remember im always looking for a good cheap used pro 5.0