Tranny swap.

cdnpont · Canadian Poncho Superstar!

Tranny swap.

guidematic · Member

Go with the 700. The bell housing is the standard Chevrolet bolt pattern and should bolt right up. I also believe the output spline is the same as the THM350, so if the shaft is the same length, you should be able to us it as is.

I once put a THM350 in place of a 200 4R in an '83 Buick that had the death knock. It was a straight bolt in.

The 0.7:1 OD in the 700 will really help fuel economy. They seem to work quite well with a 3.23:1 rear gear.

Mike

65Camino · Uber Guru

Did you ever go through with it?

66 Grande guy · Canadian Poncho Superstar!

Howdy. i put one behind a 396 that had a powerglide. I still have the car largely dissassembled but it is running to the extent of driving around the yard. It's pretty much a bolt up except that you have to heat the back mount to move it a couple of inches back and drop it a bit too. The PG console shift hooked up perfectly well with the top two detents with the Neutral, Reverse Park slipping in just where they should. So basically the drive position is the OD and the low is Drive. For me that will work I think as i don't plan to be doing any dragging just driving. For a TH 350 I think you would only lose the First gear position. You may have to fool with the length of the shifter arm to get the right leverage length.

Oh yeah i had to get my driveshaft lengthened a bit but the splines were the same.

I also bought a bracket from Classic Industries to hook the cable to my quadrajet and the lockout converter setup to get the shift points and the locking converter to work without a computer but I really haven't had it up to more that 30 miles an hour in my driveway (which is thrilling enough)

I'm looking forward the best of both worlds on this, lots of low end grunt with the lower first gear in the 700r4 and maybe some decent mileage with that big block just loafing along.

We'll see.

-- Edited by 66 Grande guy on Saturday 29th of May 2010 09:47:32 PM

slinky · Addicted!

I have the 700R 4 behind my 396 in the 69 beaumont I have about 4000 kM with it and run a 308 rear gears We went to the us got about 28 mile to a gal. We where cruising about 55 to 60 mile an hour at about 1500 rpm. Still have the two speed shifter .

seventy2plus2 · Canadian Poncho Superstar!

The president of our local club swapped the powerglide for a 700R4 in his 67 327 powered Grande Parisienne. He was very happy with the results. I think they had to do some crossmember fabrication, and some driveshaft length changes. I believe the entire thing, including cost of the tranny was about $2K.

66 Grande guy · Canadian Poncho Superstar!

Thats the kind of stuff i was hoping to hear! I have 3:31's in my car and I'll be running 15's instead of the original 14's so I'm thinking it'll be a good combo. Now I just have to find the time and money to get it on the road.

Im looking forward to a cross canada drive in that thing in about 2012 if I can swing it.

So far my cost has been pretty much exactly that.

Hey Slinky how does it go when you punch it

-- Edited by 66 Grande guy on Saturday 29th of May 2010 09:50:55 PM

-- Edited by 66 Grande guy on Saturday 29th of May 2010 09:51:56 PM

slinky · Addicted!

I pull it back into third gear and goes real good .If i leave it in overdrive its not good because i don't have the kick back hook up or the lockup .My is and older 700R-4 and it shift alright

4SPEED427 · A Poncho Legend!

I know some would disagree with me but I am convinced having the lockup functioning greatly extends transmission life due to reduced heat.

66 Grande guy · Canadian Poncho Superstar!

yeah I'd agree, I have a fairly early 700r4 in my 39 Buick without the lockup and I kind of fried it one time. Its never really felt crisp since then but I haven't wanted to get around to change it out (too many other things) Its probably worth the trouble to hook up. I have the kit parts in the tranny for that but haven't rigged up the electrical system completely yet so its only half installed really.

4SPEED427 · A Poncho Legend!

I had a TH350C in my Acadian with the 427 in an attempt to improve economy and it was very simple to wire the lockup on it.

65wagon · Poncho Master!

slinky wrote:

I pull it back into third gear and goes real good .If i leave it in overdrive its not good because i don't have the kick back hook up or the lockup .My is and older 700R-4 and it shift alright

so the cable isnt hooked up from the trany to the carb or properly ajusted and you havent burnt the trany up yet. the cable from the side of the trany controls the line pressure if its not hooked up your line pressure dosent go up to match the tranys needs

Laurentian · Addicted!

Go with the 200R4. Unless you are after serious horespower. The 700R4 does bolt in but the hump in the floor may not be big enough and the drive shaft length needs to be altered and cross member may also have to be altered. I have this experience from 73-87 chevty trucks The 200R4 bolts in just weld your crossmember back 4" and change the input shaft on the driveshaft and of course your vacuum switch for lock up torque converter. No matter what tranny you decide on you also have to change the speedo gear to calibrate the speedo.

427carl · A Poncho Legend!

Welcome Scott good info

gparis7 · Canadian Poncho Superstar!

I've got both transmissions and would consider a swap in a big block project. The 200 seems to require fewer mods to bolt in. The other thing I know from having Caprice cop cars with both transmissions is that the 700 shifts hard and is tough on drivelines. The 200 is smoother.

-- Edited by gparis7 on Tuesday 20th of July 2010 10:29:31 PM

67Poncho · Uber Guru

I have a 700R-4 in my 2+2 coupe and other than modifying the right floor pan for the 2-4 servo, that was it. Move the cross member back that 2 inches or so, change the glide differential yolk to a thm-400 unit, toss in a driveshaft from a '77-'90 B bodied Pontiac or Chevy, and go. No mods to the shaft at all!

Mine is injected so the ECM does the lock up for me!

gparis7 · Canadian Poncho Superstar!

Good to know about the driveshaft availability - saves on the fabrication.

67Poncho · Uber Guru

Had the same year of driveshaft when I had the Warner in my Rag, other than changing the front yolk to the larger output one, of course! The THM-400 drive shafts in those years take the same Precision #534G universal joint as the '77 and newer B bodies. So changing the yolk was easy...........

-- Edited by 67Poncho on Tuesday 20th of July 2010 10:52:25 PM

gparis7 · Canadian Poncho Superstar!

That makes it easy - I have an B body driveshaft from a 350/700R4 89 Caprice cop car, so I already have what I need. Thanks Vincent.

Rednek · Newbie

I personaly prefer the 200r4. they have a better gear spread and a taller OD. If your body style ever came factory with a short tailstock th400 the 200r4 will be a direct bolt in if you get that crossmember. then it would just be driveshaft length to deal with. The pump and the input shaft are the weak links in the th200r4 but there is parts available to fix that. the 700r4 has it disadvantages to. but they are both good trannys.

Professur · Guru

I'm eyeballing this swap. My th350 sprang a leak this week. I just dread the idea of trying to pull it on jackstands.

CDN2PLS2 · Uber Guru

Not Fun,but I've done a few that way.

DRI · Addicted!

CDN2PLS2 wrote:

Not Fun,but I've done a few that way.

Surprised your head fit under the car.

CDN2PLS2 · Uber Guru

I got a HairCut! DipStick.

Underdog · Veteran Member

Last year I took the TH400 out of my 75 Grand Am that had the 400ci. I used a Buick GN 2004r. The Grand Am was not highway /street driveable wirth it's 3:42 gears. (3500 at 60 mph)
The swap was effortless with a few minor adjustments.
The 200 worked great. I was timid at first but it ended up that it handled my 360ish hp, 400+ft lbs of torque smoked both tires with ease and tached along at just over 2000 rpm in overdrive.
Shortly after the swap I sold the car and the new owners are loving it.
(Ihad built the car for fun at the strip, not highway craziness!)