pancherj

Looking to step away from the 700R4 setup in my camaro since it spends a lot more time on the track versus cruising (I will swap them into my 1971 Monte Carlo). I have a tunnel mount torque arm and a nice Denny's drive shaft. So...what would you do?

TH350 or TH400?

Either will require a new transmission cross member. I think the TH350 (with a 9" housing?) will allow me to use my current driveshaft. Anyone care to offer an opinion? How about a reputable builder (trans and/or converter)? My car is making enough steam to go 11.60's at roughly 3400lbs.

DIGGLER

iTrader: (1)

for an 11 sec car i would do a th350. any faster than that and i would go th400.

pancherj

TH350 is the way I am leaning also. Can I make it work with what I have by just swithing cross members? I hate to ditch that nice drive shaft that is already set up with the 1350 U joints.

Fastbird

iTrader: (5)

I second what DIGGLER said.

I had a 700r4 in my car and it went 11.60's. I switched to a bigger cam, more RPM and I chose to go with a TH350 as the 700r4 does not like going above 7000RPM. As long as you get the long tailshaft TH350, the driveshaft will fit.

Since you are in central PA, why not take a few hour ride to ATI in Maryland and have them build you one with convertor. TH350's are a LOT cheaper than 700r4's when building to hold power.

pancherj

Good advice. ATI was one of the companies on my list. I have also used transmission specialties and Performabuilt in the past, so I would consider either of them.

five7kid

iTrader: (14)

Is there something special about your current driveshaft?

If it's stock, you should be getting something beefier, especially if you go with a tranny brake.

And, if your rear end is a 10-bolt (which it appears to be from your userinfo), you should be getting a beefier rear end as well, especially if you go with a tranny brake. That would require driveshaft modification anyway, so now's the time for 1350 U-joints and 3" DOM tube.

pancherj

Not looking for a trans brake. I do have the 1350 joints and the 3" DOM Denny's driveshaft (that's why I was looking to save it). I do still have the stock rear. So far, it hasn't missed a beat (several 100 passes). However, my future plans should be to upgrade that. As always, money is tight...

AlkyIROC

Invest in a TH400. While the TH350 will work, parts like a transbrake are more expensive and the TH400 can take a lot more abuse.

That being said, you also need a TH400 that's been beefed up especially with a 34 element sprag and hub. The TH350 can also be upgraded but at a higher cost.

In the end, the TH400 will cost more and take more to do the swap compared to the TH350 but it will be a better choice and you won't have to upgrade again when you make more power in the future.

Having your current driveshaft shortened for the TH400 isn't a big deal. You just need to get a TH400 slip yoke for a 1350 u-joint. Take the driveshaft into a driveline shop and they'll cut it down and reuse your weld yokes. You'll need the new slip yoke so they can balance it.

When you start blowing up TH350's, the cost to upgrade will already be high.

DIGGLER

iTrader: (1)

you can go pretty dang fast with a stock driveshaft. wouldnt worry about 1350 stuff with a car running 11.50's.

we were running 6.4's in the 1/8 with a long tailshaft th350, stock driveshaft, and stock rearend in a '97 z28 last year.

Edwardgp

My transmission guy beefed my th350 up so good, man that thing has stood up to abuse.

pancherj

I was wanting to keep the cost of the entire swap (transmission, converter that flashes to around 4500 and new cross member) at around $2000. It seems possible with a TH350 (no trans brake), but not a 400. I do agree that a 400 can take abuse. Decisions, decisions...

ZONES89RS

iTrader: (2)

I found (stole) a th400, TCI competition series off Craig's list for 500$, reverse manual valve body, thing is a beast. I would look into one for sure, 1100$ or so last I checked new, you would have 900 left for converter, DS work, yolk and x member, I build my own x members.

pancherj

Thanks for the comments Zones. No personal experience with TCI (except an old steetfighter torque converter which worked very good for the price). I'll have to look into them. There is always the option of finding a core and doing it myself. I have done a few with good success, but I have so little free time to mess with that stuff anymore. Once you buy all of the good stuff, the cost savings aren't tremendous either.

ZONES89RS

iTrader: (2)

Yea, luckily the used market in Houston is HUGE. Great deals are what builds my rides, I am a poor man with moderate dreams, so I manage. Lol

Shagwell

TH350's can be built with mostly stock internals to run down bottom 10's, IMO once you go into the single digit range they start needing upgraded parts and still aren't very reliable(thus no longer cost effective to use). - I would NOT run a t-brake in a 350, just the same as not running one in a 4L60; if you are at the point of needing it, then you are beyond the transmission.

Earlier th400's came stock with the 34 element sprag & aluminum apply pistons. Since they are OE parts even with a later core that needs them swapped in I personally don't consider them "upgrades" as many builders seem to. - Not that I'm not on borrowed time, but we have roughly 100 passes in the low 5's and will be solidly into the 4's next outing on what is essentially a stock internal th400 with a good rev man/t-brake vb.





If it were me, for what you want out of the trans & since you already have the upgraded stock length DS I would probably go with the long tail th350.

pancherj

Lots of good input so far...thanks! An additional question: I am thinking I want an 8" converter that stalls at 4500RPM (behind my 350). Are my best and only choices places like ATI, COAN, etc that will cost around $800?

Fastbird

iTrader: (5)

ATI will do a treemaster 8" for a decent price. If you go to the Englishtown nationals (this weekend) they have their truck there and will take an order and give an event discount (10-20%). That is where I got mine last year.

1badeagle

iTrader: (2)

Go with a 4l80e. It will hold all the power you will ever make and you keep your od.

AlkyIROC

Since you're considering more track than street time, another option is a powerglide. A basic V8 powerglide with a 1.76 gearset can be upgraded for a lot less than beefing up a TH350 or TH400. The powerglide is roughly the same length as a 700R4 and long tailshaft TH350 so driveshaft length isn't an issue.

The transmission weighs a lot less. It uses up very little HP. Upgrade parts are very cheap compared to TH350 and TH400. The first thing you need to do is upgrade the input shaft since the OEM one is weak. Upgrade to turbo splines and use your current converter.

1gary

you nailed that one.

DIGGLER

iTrader: (1)

a glide with 8" 4500 converter will drive like crap on the street. it will become a "race car" at that point, imo.

i would do a 3 speed with a more streetable converter and gear. if you want to go faster, add a turbo/supercharger/nitrous.
4l80 would be an awesome trans, but you will have alot invested in that setup by the time you get the $800 junkyard trans, $900 converter and electronic trans controller.

pancherj

I thought very briefly about a glide. I do like to drive my car to work and cruise with my kids when I get a chance. I think that leaves me with a 3 speed. Remeber, this is just a pump gas 350. The 700R4 has held up fine. I don't like the steep first gear and the RPM drop on the shift. I also want to step up the converter because a 3600 is not enough. The 700 will slip nicely into my 1971 Monte Carlo.

If I decide to do my own TH350, what vehicles came with the longer tailshaft? I have a TH350 (needs rebuilt) with the short tailhousing. I believe they make a spacer kit to use that transmission in our cars, but that sounds sketchy to me.

DIGGLER

iTrader: (1)

im not certain on which cars had the right tailhousing, but i would think a caprice or something? possibly a pickup truck? there was also a th350c which had a lockup converter. that might make a decent setup too, but converter might get pricey. i would for sure spend most of my money on the converter. do a decent trans, and a GOOD converter. fti, ultimate, or chance.

Shagwell

Stock th350 internals will handle as much as stock glide internals, and the stock 400 internals will out do both. Add in a heavy car that does see some street use and isn't making single digit power, a 2-speed just isn't a good choice IMO. The converter is going to have to be absolutely perfect for the combo to not be a slug on the track and then it's not going to street cruise worth a crap.


Glides have their place, but a heavy strip/street car is definitely not it. IMO, a heavy anything is not it.

ZONES89RS

iTrader: (2)

Personally, a 4l80 would be the sweetest, tough as a 400, cruises like a 700R.

1badeagle

iTrader: (2)

Exactly. I dont see why more people dont run them.

ZONES89RS

iTrader: (2)

Pricey depending on how you end up with them. Will hold 600, but not old and raggedy. Rebuilding them for eleventy billion hp costs plenty.

Shagwell

If you really drive the car a lot/higher speeds then it's justifiable, but otherwise it's a rather expensive & heavy trans. - I love them, but they're not for everybody either.

mw66nova

iTrader: (13)

th400 TTFMF!

listen to shagwell

Fast 383

iTrader: (2)

Whoa.

Shagwell

Three local 4th gens have been solidly in the 9's repeatedly on mostly stock th350's, just a combination of the typical "better era" specific pieces. Not totally gutted out cars either. Coming from two different builders it doesn't seem they're just "fluke" luck. - Personally I either have OD or have a th400 though(lol).

Shagwell

dbl post

mw66nova

iTrader: (13)

th400 or 4l80e....

i like my CER th400 and Transmission Specialties converter

Edwardgp

Yes sir I am high on my th350 talk about taking some abuse.