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Hi All,

So i have an 81' vette with a 383 stroker ready to go in.

I went to town on this engine the only thing original is the block.

I want to upgrade the TH350 i now have (not TH350C i got rid of that S**t) to hold up to the 400+bhp & 400+ft/p torque i will be producing.

I know first i need to change the intermidiate sprag on the trans as that is a common weak point.

I want you opinions on what other upgrades i could do to improve the ride.

First lets clarify that i do not want a TH400, a 700R4 or the much loved 200R4. the car is designed for a TH350 its a bullet proof trans and i will not change it.

Cheers all,

Scott

P.S - ill post pics along the way.
 

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drag race addict
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1,392 Posts
Hi All,

So i have an 81' vette with a 383 stroker ready to go in.

I went to town on this engine the only thing original is the block.

I want to upgrade the TH350 i now have (not TH350C i got rid of that S**t) to hold up to the 400+bhp & 400+ft/p torque i will be producing.

I know first i need to change the intermidiate sprag on the trans as that is a common weak point.

I want you opinions on what other upgrades i could do to improve the ride.

First lets clarify that i do not want a TH400, a 700R4 or the much loved 200R4. the car is designed for a TH350 its a bullet proof trans and i will not change it.

Cheers all,

Scott

P.S - ill post pics along the way.
Your quote in bold isn't true. If it was GM would have put it behind everything.
Just clarifying that for ya.. ;)
 

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Some TH350 have less clutch frictions, this can be corrected by machining pistons to the correct size, different thickness steels and retainers can be used to correct sloppy clutches, a hardened spragg, extra bush on the sun gear, higher stall converter and a governer calibration kit will move WOT shift points. As Redvictor pointed out broken transmissions keep him in business
 

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drag race addict
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1,392 Posts
Redvictor - what kind of cost am i looking at to get you to upgrade my trans to cope it a more powerful small block?

What info would you require?

Thanks

Scott
A HD rebuild without a converter overhaul, with my shift mods is around £700 + vat inc labour/parts etc. Add a 36 element drum and outer race and that would be £350 + vat extra from the last time i bought one. That is if everything is in good shape hard parts wise in the trans. If not i have some good core parts available at reasonable prices.
Stripping it to let you know the exact price is a better way...
 

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agreed The question is well built, which can cost potentially more money than a stock built th400, yes they use slightly more power . the same can be said about 9 inch axles. Most people want the strongest but do not have the engine to make use of it.
I have a th350 behind a 383 truck motor 4 wheel drive , and that has been extensively modified, if a th400 would have bolted up i would have used one.
 

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if you install a 700/200 you really should install a lock up kit, this is a wiring kit that uses a vac signal from the engine to get the converter to lock and unlock as it would have done in its original vehicle.

Just a bit of wring, no biggy.

The 200 is a good swap in the vette as it's a smaller box than the 700 and doesn't require the prop to be shortened unlike the 700.
..but they were never a hi-po box so they do need to be built, the Buick GN boxes were stronger apparently.
I appreciate you want to stick with the 350 though.

P.s I've got a '71 vette with a Tremec TKO 600RR 5-speed so i'm familiar with them.

Here's some 700/200/350 pics -

http://s877.photobucket.com/user/aaroncorvette/library/Stude engine rebuild?sort=3&page=1
 

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I use a stock TH350 on my MGB. Its been dragged since 2006 and is still working ok. It was brand new in 2006. I do have a spare to drop in with trans-brake fitted so I can send the stock box to Andy for a refurb at the end of this season. I guess a lot depends on the weight of the vehicle as well. The MGB is only about 2600lbs. On Nitrous only it made 400hp with 600ft/lbs. Now with the blower and less nitrous it makes just under 600hp and 545ft/lbs on a safe tune. I run slicks and only race the car on the Drag strip. Actually!!! Make that 2800lbs with me in the car :)

When I roll the MGB out in a few weeks I'll be hitting it harder with a better tune in the engine to see how it does. I think I will need to look at the converter next as well. I think it may not be up to the job for the next phase of the cars tuning. I'll have to talk to Frosty about the converter soon i think.

Perry
 
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