Question about TH350 sitting for 20 years

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Donmcgowen
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Question about TH350 sitting for 20 years

Post by Donmcgowen » Thu Apr 16, 2015 11:34 pm

So I bought my 68 Camaro 20 years ago and it's been sitting ever since. I'm building a 500hp 377SBC. I have a 32-3500 stall and 4.11 rear. What should I have done to the trans? I really would like a reverse shifter and have it beefed up to handle 600hp with NOS. Or should I just go with one of those B&M that Summit sells for $1000 rated to 550hp. I feel like I spend just as much or having someone redo my existing trans.

Just curious what you guys would do. Or, does anybody have a nice beefed up TH350 that can handle the power for sale?
Don McGowen
1968 Camaro
377sbc - forged crank, 6" rods, JE pistons
10.5:1
242/252 .580/.600" solid roller
ported Dart II Sportsmans 200cc
Holley Dominator intake
750 Demon carb
1 3/4 Hookers
3-3500 stall
TH350
4.11 rear

OILEAKY
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Re: Question about TH350 sitting for 20 years

Post by OILEAKY » Wed Apr 22, 2015 1:49 pm

Just pull the pan and install a new filter, drain all the old oil out of the converter, put it back together, add oil and drive it.
That's worked for me every time.

cgarb
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Re: Question about TH350 sitting for 20 years

Post by cgarb » Thu Apr 23, 2015 5:32 pm

If you want to build a nice trouble free TH350...or have built...that will handle that kind of horsepower, it doesn't take a whole lot of exotic parts. In my trans I used an ATI valvebody without the band apply. Its a drag only car, that helps with ET, for a street driven unit you may not want that. Talk with them they can help you with what they would recommend. I also used TSR Racing transmission 36 element sprag unit. I've had an ATI sprag, it worked but the TSR is way cheaper and a nicer sprag in my opinion. He will also sell parts to his unit where ATI will not. Thy will only recondition yours or sell a new one. With those 2 parts, my trans is holding up to high 1.30/low 1.40 60ft times in a 3300lb vehicle. 2 years on my trans from last rebuild and we pulled it apart this year and you could still read the print on the clutches. No metal anywhere. We replaced the gaskets and seals, new fluid and run it for 2 more. One thing I did learn over the years and TSR informed me of this is to do burnouts starting in 2nd gear. He said it don't chatter that sprag unit. I start in 2nd come out in high gear. Since then no issues at all.

mike hohnstein
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Re: Question about TH350 sitting for 20 years

Post by mike hohnstein » Wed Apr 29, 2015 8:25 pm

Probably won't heed but put a glide in it, using a 30 spline input your converter will work. Less parts to break and will be just as quick if not a little quicker compared to a 3 speed.

cgarb
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Re: Question about TH350 sitting for 20 years

Post by cgarb » Fri May 01, 2015 12:57 am

In my experience in a heavy car the TH350 trans is faster due to the first gear getting the car moving quicker. My car picked up a tenth going back to a TH350 from a glide. I had a custom converter built for both trans for my specific application. I liked the glide, but I couldn't get the tree with how slow it reacted. I think with High HP lightweight cars glides are the faster option. If they were faster across the board, you would see glides in every stock and superstock car in the staging lanes.

mike hohnstein
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Re: Question about TH350 sitting for 20 years

Post by mike hohnstein » Fri May 01, 2015 1:56 am

Yeah well my experience is different. I'm not a glide nut hugger but they are a better choice for most applications. Not talking Stk/S/Stk here where guys flog facsimiles of oem offerings from the distant past. Just average joe's trying to get down the track with a minimum of BS.

cgarb
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Re: Question about TH350 sitting for 20 years

Post by cgarb » Sun May 03, 2015 11:05 pm

No doubt a glide is about as simple and tough as an automatic transmission can get. My dad builds my transmissions so im kinda spoiled in that respect. I don't have transmission troubles much. 3 speeds can be a little tricky to get right, mine is just as trouble free as any high dollar glide ive seen. Im not making 900hp either. Definatly more than one way to skin a cat. Glides make a car easier to drive. Simple and effective for sure.

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