I own a 67 RS/SS with the # matching 350cid 12 bolt rear (ratio unknown)and a TH400 transmission. Originally it came with a powerglide, but the rest of the car is totally stock. I have problems with the 400 shifting to quickly and with no down shift when punched. After diagnosis it will need a new modulator, I think is what he said, and the front seal replaced where it has been leaking, probably because it sets to much. Anyway I am told it will cost about $700.00 to $1,500.00 to fix at a shop. I have been toying with the idea of a muncie 4 speed for a while now, but don't know if the TH400 would be a better suit, or even installing the original type powerglide back in. Here are my questions:
1. which transmission would bring the car top dollar at the car auction ?
2. Are TH400 gears longer than the TH350?
3.Is the TH400 to big for best performance with the 350cid?
4. would a performance stall converter on the TH400 be competive with the Muncie?
5. would a stall converter on a powerglide be competive with the Muncie.
6. would the TH350 fit the 350 cid better?
Any additional input would be greatly appreciated.

1. Depends on if the buyer wants it original or not.
2. TH-400 is a longer trans.
3. I would stick with the manual trans, or use a TH-350 if you want an auto 3-speed. Much less power loss internally than a TH-400. Or, put in an overdrive trans like many do.
4. Absolutely. If you go auto, email me and I can give you some suggestions.
5. Yes, although the Glide only has either a 1.76 or 1.82 low gear, thus my thoughts that a TH-350 or overdrive would be a better choice for a mild motor combo.
6. Yes, see #3.

That is waaaaaay too much to be charging to overhaul the trans IMO. I do the TH-350/400's for $175 + parts when sent to me out of car. Overhaul kits are just over $100, so even if it needed a new pump, etc. it is rare to see them need more than $400-450 or so. As for no downshift, the TH-400 uses an electric switch on the throttle to send power to a solenoid near the valve body in the trans to complete detent downshifts. Look to see if you have power to the switch, and that it is adjusted correctly so that it closes at full throttle. If okay there, then see if you have 12v at the wire where it attaches at the trans when at full throttle. If okay there, the wire could have come off inside the trans, or the solenoid possibly may be bad. Easy to change, drop the pan and you get right at it. The quick shifting can be resolved with a kit that recalibrates the governor, as the modulator only affects part-throttle shift quality and does not change shift points too much, as the governor does that with its internal springs and weights. Or, toss the 400 the trunk and drive on up here to me, lol.

Agree with Steve on all counts. But, if car is equipped with a TH400 now, and want to change to a TH350, 5/6-spd, or 4-spd Muncie, alot of parts gathering will be needed. Clutch/pedal assembly, whether mechanical or hydraulic, crossmember, driveshaft, shifter, electrical wire harness, etc. will have to be purchased and installed.

TH400 trans is a physically longer length than the rest.

Alot of planning and money will be spent.

A TH350 is the correct automatic trans for your car if it's a real '67 SS. No powerglides used on the '67 SS. I agree with the others about the pricing to fix your trans to a degree. I've seen labor rates vary from $40 an hr to $100 an hr depending on geographics. Close to half your charges will be for pulling and installing the trans and if switching from one to another it will be even more spendy because there will be fabrication time and/or additional parts like shortening a drive shaft or installing the pedals and clutch linkage...

Repairing your existing trans is your least expensive option and what that costs will depend on what you can do yourself. There are other transmissions that may be better suited, weight, power-loss and gearing but there really is nothing wrong with running a TH400 behind a 350ci mill... Back in the day, guys were yanking powerglides and th350's like the cook at I-HOP flips hotcakes and replacing them with th400's...

Originally posted by DjD:
A TH350 is the correct automatic trans for your car if it's a real '67 SS. No powerglides used on the '67 SS. Sorry gotta disagree, T-350 trans didn't come out untill 69. if you 67 SS was originally a small block and an automatic. it came with a Powerglide.

Hay, I appreciate all the info, this will help allot, I will E-mail you on the TH350 but I'm still a little confused about the original trany I thought the M13(Auto 3 speed), M20(4 speed), M21( 4speed), and M35(Powerglide) were all transmissions available for the 67 350cid SS. According to the RPO Codes at the camarohomepage.com, Is this wrong? This is prodably not the right place for numbers, but for reference my vin is 124377L164097, and the block reads L7164097 V0623MU, and my Cowl reads 67-12637 LOS20787 C607
ST 742-Z R-R
TR E ZEMG 3SK
4P
I also have the protect-o-plate if this will help.

I stand corrected... m35 = pg m38 = th350... my error...

Thanks again, this is a wonderful web sight. I am fairly new here, but I am constantly amazed by the amount of help,information and technical data available here. graemlins/beers.gif
Ok, I'm thinking along the lines of the TH350 but I don't know if I can hold the horse bug from biting. My question is will the TH350 be strong enough to handle a souped up 350cid, lets say upto around 400HP or slightly better. If not maybe the Muncie ?

If you have the th400 in the car already and it works, why not get it freshened up and keep on driving it? If you decide to add a bunch of power you still won't hurt it.This is by far your cheapest option.

That price is WAY out of line. If you can pull it out yourself you should be able to get it built for $500 or less including parts (no matter what the labor charges are). I agree if you have the shop pull the trans and install it you are looking at twice the price.

To repair/replace a front seal and change the "modulator" (if Steve says the modulator is not the problem I would listen to him)is VERY minor and you could do that yourself and the parts are less than $50.

Take your time and think this through, you could end up spending a bunch of money unecessarily.