TH350 Clutches / Modifications
 

I am attempting my first automatic transmission rebuild and am wondering what clutch/steel count I should use in the various clutch packs for my application.
I will be running Red Alto clutches with Kolene steels along with a manual valve body with no band.

From my research I have found a few modifications I am going to try like enlarging the direct clutch cooling holes (and adding a few more) along with adding bushings to the sun gear and running a wider direct clutch/drum bushing. Any other tricks I should implement?

The application is a 3400 lb small block car running 11.30's
Thanks in advance,
Chad

Re: TH350 Clutches / Modifications
 

If you're drag racing, you don't need the extra holes in the direct piston. They won't hurt, but they won't help anything either.

If this is a bracket car, 5 low reverse, 5 forward, and 5 direct clutches, with no cushions will work fine, and 3 intermediate clutches, with no cushion, will be fine there. Replace the wavy cushion plates with flat steels.

Re: TH350 Clutches / Modifications
 

Hi Alan,

Got to be careful about not running the wavy steel on the intermediate clutch pack because sometimes the flat steels interfere with the apply piston return spring retainer. This will also give you an incorrect clutch pack clearance...

Just a heads up,
Bob

Re: TH350 Clutches / Modifications
 

I read a company made a 700r4 low work?????

Re: TH350 Clutches / Modifications
 

Daran, what they do is take the ring gear off of the 350 rear planetary, then cut the ring gear off of a 700 rear planetary, and weld it on the plate of the 350 planetary, they also weld a plate on the 700 planetary carrier to set the end play for the thrust bearing. Then they take the rear piston for the 350, and turn the ID in a lathe to clear the 700 ring gear.

That's how you get a 2.75 low gear for a 350. I just put one in the Super Stock Camaro, because we can't get the right rear gear to run a 2.52 low.

Re: TH350 Clutches / Modifications
 

Bob, it may be possible to have that happen, but I've been building them that way for about 25 years, and never had a problem. I usually get 400 passes out of one of my 350's, and that's in the AA/SA car. I just replace the wavy with a flat steel.

Re: TH350 Clutches / Modifications
 

Alan I really could use a 3.06 low T-350 :)

Re: TH350 Clutches / Modifications
 

Daran, I think Coan can get you close, but the price and the RPM drop will both probably be ugly and painful.

You'd need to change the front planetary out with something, and you'd end up with somewhere around a 1.75 to 1.8 low gear, a 1.2 to 1.25 drop in gear ratio is a lot, especially for an engine you think needs a 3.06 low gear. My big complaint with the 700 R4 is the low gear is too low, and the drop between 1st and 2nd is too big.

Re: TH350 Clutches / Modifications
 

Alan,
Thanks for the info on the clutch/plate counts and also the tip on replacing the wave plate with flat steels.
What is the theory behind drilling the holes out on the direct clutch? It is just a cooling enhancement for street driven cars?

This is a race only car that is slowly inching it's way to I/SA as I save up the funds to replace the bracket engine with a legal stocker.
Thanks again.

Re: TH350 Clutches / Modifications
 

My latest brillant idea, 1966 Impala SS/NA 283/220 low budget!!!! 5.86 gear stocker radials, footbrake stock t-350 with 8" converter approx. 4500.
60 ft 1.86
1/4 12.80 on a 12.15 index
mph 106

My U/SA left harder :)

Car will never be a killer, just looking for consistancy 2-3 under.

Re: TH350 Clutches / Modifications
 

I put a spacer under the int. piston so it doesn't return as far , thus tightening the clearance and quickening the apply.

Re: TH350 Clutches / Modifications
 

Chad, I've seen that modification done, but not seen any real gain.

Honestly, the transmission for Stock will be very different. In fact, for your car, in I/SA, I'd be looking at a 200 Metric from McClay or Arnett. To convert your 350 to a class transmission, you'll need to replace both drums with aluminum drums, as well as having some other stuff lightened. The difference between what you're building now and what you'll need for Stock is about a tenth.

Re: TH350 Clutches / Modifications
 

http://www.truckinweb.com/tech/0510t.../photo_03.html


What do ya'll think???

Re: TH350 Clutches / Modifications
 

One of the reasons for drilling out the "cooling holes" in the OD of the clutch housing is to allow trapped oil to escape. The oil could build up on the OD of the clutch plates, when the housing spins and drag the clutch on. By drilling holes in the correct areas of the splines, the oil will exhaust and won't apply the clutch. Usually this trick only is done on the direct clutch housing.

Re: TH350 Clutches / Modifications
 

Daran, that is exactly what I described up thread. It yields a 2.75 low gear, because the front planetary remains unchanged.

That photo is merely a picture of a stock TH350 rear planetary carrier next to a stock 700 R4 planetary. That's not what it looks like when ready to install.

Re: TH350 Clutches / Modifications
 

Daran, You're way under geared and about a thousand short on the stall speed for openers.

Re: TH350 Clutches / Modifications
 

Mark, I was thinking 6.17 gears, if it's a 12 bolt, and about 6000 stall, if he's got a Super Stock engine that will spin anything like it should. Not sure a 2.75 low will work because of the drop between 1st and 2nd. That extra point and a half of gear is a big deal to a small engine with no torque, especially in a heavy car.

Going from 2.52 in 1st to 1.52 in 2nd is not the same as going from 2.75 in 1st to 1.6 in 2nd, even though the 1st is low, the extra 0.15 gear drop makes a bigger difference than some think, because they forget the car is going SLOWER when it comes out of low gear with a 2.75 than it is with a 2.52, that amplifies the drop.

Re: TH350 Clutches / Modifications
 

I imagine Daran is trying to pick up the 60' with the low gear change.
If he had the right rear gear, he wouldn't need the low gear set.
We used about 5300 stall in a 283/220 SS car, about 30 years ago.
He needs a 6.40 ford or a 6.50 Dana to do it right.

Re: TH350 Clutches / Modifications
 

We've got a 6500 in the SS/EA car. I've got a 2.75 low in it because I can't get the 5.57 they say I need, the closest I can get is a 5.38, they don't have a 5.57 for a Dana 60. I'm not sure the RPM drop won't hurt me a little. But I need the car to move harder, and I think between the stall and the big block, I can pull that drop okay.

Re: TH350 Clutches / Modifications
 

Just installed a light T-350 2.75 low with brake this time. On the brake the converter is going 5200. Heading to Gainesville tonight to try. Hoping for a 1.5 something??? 60 ft. I have a 12 bolt in it with 9x30 radials. Perhaps a 6.14 and a ET 29.5 will be next.

Re: TH350 Clutches / Modifications
 

You need to check on a Billy Lynn metric trans. He's a lot more reasonable on price that McClay and his stuff will work just fine in I/SA.

Re: TH350 Clutches / Modifications
 

Well tested Sat. night and everything went well, lost in the final of the index race. Trans made car much easier to drive leaving on the mat. Unfortunately the car still only went 1.80-1.81 60 ft. The car just will not react. The front end does not move at all. I believe I am WAY under geared but I have to work on the suspension. Any front spring recommendations? Can I remove front strut rods to free up the front. I have CE 90/10 shocks on loose setting. Car just is not working.

Re: TH350 Clutches / Modifications
 

Daran, are you shifting before the 60' clocks?

Re: TH350 Clutches / Modifications
 

x2

Re: TH350 Clutches / Modifications
 

No WAY! I think closer to the 330. I am beginning to think 28" slicks now :) I will need to get a video of it to show you how pathetic it is. 2.52 vs 2.75 low made no difference, just shift sooner

Re: TH350 Clutches / Modifications
 

Daran, what's in the engine? Is it making any power?

Re: TH350 Clutches / Modifications
 

NO! They are the triangulating point for the lower A-arm.
What's done to the rear susp.? If it's too stiff, the front won't lift with that long wheelbase.
I never had one of those cars that wouldn't lift the front end, with stock springs.
It sounds like the engine combo is messed up .
Need details ...Cam ,manifold, carb modifications , headers etc.

Re: TH350 Clutches / Modifications
 

Engine is by no means Stellar!!! I built it :) It does pull clean and mis free to 7500 that's as high as I've gone so far. It sounds good not stellar but good. Trans works perfect. Rear suspension is coil over shocks with aftermarket adj control arms in factory locations with adj panhard bar. I have -5 on pinion and 0 on tail shaft. I would like to raise the upper control arms with taller brackets to change IC like the no hop bars do. I just removed the front strut arms (had to cut drivers side) but front end feels much better just by hand. I would think a 18" long 4 link bar with a heim on each end may work. I need a fresh set of coil springs for the front and moroso doesn't show anything. Engine makes enough power to pull the wheels I would hope!!!! Car does not lift the front end 2" when I let the button go at 5200.


P.S. it took a torch and a 5 ft. pipe to break the strut rod nuts loose ! LOL

Re: TH350 Clutches / Modifications
 

Better weld it back together and put them back on. Not LEGAL and totally unsafe .
I'm surprised nobody else told you that yet . Everybody must want to watch the fun...

Now, if you had a FWD conversion, you'd get carte blanche from NHRA
(No Hot Rods Allowed)

Re: TH350 Clutches / Modifications
 

http://www.globalwestperformance.com...trut-rods.html

Mark it's all bolt on so I don't forsee a problem. I believe your right on the gearing and the rear suspension being bound up (Tight) I truly wish I just had the factory rear arms with the factory springs at this point. Something is dead wrong.

Re: TH350 Clutches / Modifications
 

Re: TH350 Clutches / Modifications
 

Hay Mark, Wont a 6cyl spring work with that combo, I remember Fedun used them. What bushings are in your A- frames? That combo should Jump up with no problem.

PS Great looking car

Re: TH350 Clutches / Modifications
 

Daran,
I'm not sure the front suspension pieces are legal, and they certainly are not necessary. I'd get a ruling, in writing, from NHRA tech. Actually, I just wouldn't buy them. If the cars can be made ot work well in Stock Eliminator without them, and they can, then there's no reason to buy them, that's money better spent elsewhere.

I'd be taking the shocks and springs off, and checking the suspension on both ends for binding, and correcting what I found. Then I'd look at the upper bar mounting locations on the rear housing, as you were talking about earlier. After that, I'd take the 2.75 low back out, swap to a 6.17 in the rear, and see about getting the stall speed up around 6200-6600.

Re: TH350 Clutches / Modifications
 

Definately more gear and converter, right now gonna work on suspension until I can get some daylight under the tires. If anyone has a front spring part number I'd love to hear it. I will probably use fresh control arm bushings with teeth removed. I'll keep you all updated if I find the problem. Thanks everyone

Re: TH350 Clutches / Modifications
 

Daran, I'd go Del-A-Lum if I were going to keep the car, along with low friction ball joints, and long uppers. The Del-A-Lum stuff with grease fittings will stay free and work well forever. That's a job you only want to do once.

Try 6 cylinder or small block 3 speed springs, that should do it, usually Advance or the 'zone can get them.

Re: TH350 Clutches / Modifications
 

Darin I might have the parts you are looking for. If you are interested you can call me at Home # 321-632 2171 cell# 321- 412-5196 . Kenney Kelley

Re: TH350 Clutches / Modifications
 

I will call you Kenney, looking for stock rear control arms and a drivers side front strut rod for a 65-66 Thanks