A little advice from a TH350 expert please

[daw285]

Hello every one,
I have a few questions for a TH350 expert. I asked Summitracing these questions but they were of no help to me (even though I’m trying to buy their parts). They keep wanting me to call in but whenI do they don’t seem to know the answers I want to know. If any TH350 experts can lend a hand in answering these questions it would be most appreciated. This is what I sent to summit:

I'm building a 1927 Ford Model T with a sbc 383 stroker. The engine makes about 500-550hp and is built to take a 300 shot of nitrous. This will be mainly a street car but I do plan on “getting on it” at the strip quite a bit. I'm running a th350 for a trany. I bought the trany used. It was used on a mid 80's camaro 1/4 mile drag car. It was rebuilt from what I can tell (red clutch disks and a few other things) but WELL used. The camaro was running a BBC and I'm guessing it had quite a bit of horse power. Since I knew little about the trany I decided to rebuild and beef it up a bit. This is my first transmission rebuild by the way. Most of the trany looks good except for a few things. First the Sun Shell has indents in the slots from the friction plates. I believe these indents, which are about a 0.026" deep, are from the transmission shifting very hard and with a lot of horse power on it. I have found a replacement sun shell in very good shape but it is about 0.25" thick and the one I have is only about 0.105" thick. First question, will this new sun shell fit my trany and work for me? They guy I bought it form said it would fit any th350.

Now for the questions that Summit will actually make money off of me with...The input shaft that's in the th350 has some deformed splines from the torque converter. They are deformed to the point that I want to replace it just to ensure I will not have issues from it in the future. It has become apparent to me the input shaft is part of the front pump. I see Summit offers two front pumps that I'm interested in. Here they are: http://www.summitracing.com/parts/TCI-313400/, and http://www.summitracing.com/parts/HUP-HP3230/. These are Low-Volume Pumps. Question 2, are these pumps suitable for my application? If so which is better for my application? I see the TCI has a bolt in stator and the Hughes has a cast stator. What are the benefits of each? What is the purpose of having a low volume pump? I would think a high volume would be better?...

Final question. I wanted to put a shift kit in the th350, or at least replace whatever the last guy had in it. After some research I decided to go with the TransGo Performance 350-1-2 which I purchased from Summit, http://www.summitracing.com/parts/TRG-350-1-2/. It seems to replace any and all of the parts the last guy could have changed out or modified in the valve body. I wanted a kit that would allow me to utilize my B&M Megashifter (http://www.summitracing.com/parts/BMM-80690/) and be able to be run in both automatic and manual shifting as needed. My question, did I choose the wrong thing? Should I have gotten a Manual/Automatic Valve Body such as summit item number http://www.summitracing.com/parts/HUP-HP3222/ or http://www.summitracing.com/parts/TCI-322200/ or http://www.summitracing.com/parts/TAC-23250/? Please advise and please let me know if there is anything else you think I might be missing.

Thanks for your time,
Dave

 

[Mike]

Moved from Engine and Driveline Articles...

 

[daw285]

Sorry Mike. I'll pay closer attention next time as to where I post these things.

Thanks,
Dave

 

[RPM]

My advice would be to call one of the companies that build these such as TCI. Be careful about mixing brand names in it also a part X from TCI may not work well with a part Y from B&M.


For what it is worth I run a full manual reverse valve body, from TCI. Yea you have to shift it but no big deal. Only draw back is no braking coming down a long steep hill.

 

[Lee_in_KC]

My understanding is that the intermediate sprag race is the weak point in the TH350. I broke my first one after only about 500 miles. Second one (hardened race part) is still going after about 2500 miles behind a 6-71 blown SBC making around 500 hp/450 ft/lb.

 

[daw285]

Thanks for the input guys. I heard about the sprag issues these things have. Do you use just a hardened race or a whole assembly like this one from TCI http://www.tciauto.com/tc/th350-iron-drum-hd-sprag-assembly.html? At this point it seems like I should have just bought a transmission ready to go from one of these places. After the sprag assembly, front pump, bushing, thrust washer and seal kits, shift kit, and torque converter I'm going to have over $1,150 in the trany and still need a cooler...

 

[RPM]

Has anyone tried ATI racing transmissions? The inlaws use there stuff in their race cars and speak highly of them.

http://www.atiracing.com/products/trans/350/index.htm

 

[409T]

Has anyone tried ATI racing transmissions? The inlaws use there stuff in their race cars and speak highly of them.

I had a friend who rebuilt Mercedes transmissions only, but when he needed something different for a customer he always bought ATI.

 

[donsrods]

I've never heard anything bad about ATI, if that counts for anything.

Don

 

[Screaming Metal]

Just curious, with a motor thats gonna be a 383, why not a powerglide, if your gonna go down the track in it? Just Curious. It'd be mucho fast, as light as these cars are! A 350 and 400 are good for perf. and cruising......ATI is good.
Then you got B&M's complete trans in a box form, replace your front pump, put just a touch of converter in it and have fun.
With the economy the way it is, walk into a trans. shop, ask if any of the guys play with hotrods or race (theres usually 1!), tell him you want a trans built. He already knows the ins and outs, make a friendship, and have a fairly cheap, (Monetarily speaking that is) really hi-perf. trans built. Help do your part to help the ecomony....
Or go with the B&M TransKit....it has everything in it for a street/strip trans in one box! Other makes have the equivelant now.....even converts your valvebody. Even has complete directions!
Just my 2 cents........

 

[Wild Mango]

Thanks for the input guys. I heard about the sprag issues these things have. Do you use just a hardened race or a whole assembly like this one from TCI http://www.tciauto.com/tc/th350-iron-drum-hd-sprag-assembly.html? At this point it seems like I should have just bought a transmission ready to go from one of these places. After the sprag assembly, front pump, bushing, thrust washer and seal kits, shift kit, and torque converter I'm going to have over $1,150 in the trany and still need a cooler...

Use the whole assembly from TCI and forget about it as a possible problem. I like the TCI full manual valve body with engine braking in the intermediates, and you don't shift towards neutral and reverse. Simple and no shift kits etc.

 

[Screaming Metal]

Use the whole assembly from TCI and forget about it as a possible problem. I like the TCI full manual valve body with engine braking in the intermediates, and you don't shift towards neutral and reverse. Simple and no shift kits etc.

What he said! I shift mine like a manual trans., just without the clutch!