81 vette tranny work question
Thread Starter
Instructor
Joined: Aug 2007
Posts: 116
Likes: 0
From: Temple TX
81 vette tranny work question
Hey all. My motor is doing great but my tranny just went out. I was hoping I could get some ideas on see some options. It is the TH-350 lockup.
I can either rebuild that tranny and leave it be or I can put something else in it. It needs to be able to hold 450 hp. Anyone know of a good tranny to put in? I am also wanting to get rid of the lockup while im at it and adding a new torque converter. How does 2200-2400 sound? I can spend 2 grand, maybe alil more if need be. Thanks! Also, Is it a pain to switch from auto to stick? I wouldnt mind doing that either if I could squeeze it in my budget.
I can either rebuild that tranny and leave it be or I can put something else in it. It needs to be able to hold 450 hp. Anyone know of a good tranny to put in? I am also wanting to get rid of the lockup while im at it and adding a new torque converter. How does 2200-2400 sound? I can spend 2 grand, maybe alil more if need be. Thanks! Also, Is it a pain to switch from auto to stick? I wouldnt mind doing that either if I could squeeze it in my budget.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
You can do this for well under $2k.
Build youself a TH2004R, its a 4 speed auto with overdrive and lockup. Lockup is your friend, it improves gas milage and saves heat.
I built mine from a core and ebay parts, new 2200 lockup converter and built my own cross member all for about $900.
That includes the hot rod parts inside
Build youself a TH2004R, its a 4 speed auto with overdrive and lockup. Lockup is your friend, it improves gas milage and saves heat.
I built mine from a core and ebay parts, new 2200 lockup converter and built my own cross member all for about $900.
That includes the hot rod parts inside
Advanced
Joined: Jan 2005
Posts: 71
Likes: 11
I would go this route:
http://cgi.ebay.com/ebaymotors/GM-TH...mZ150204155170
I bought a built c4 auto for my turbo 63 falcon from them, and I am 1001% satisfied. They are very accomodating. I am sure they'll build whatever you want. This TH350 is rated for 500hp and comes loaded with track goodies including a custom stalled converter.
I have absolutely no connection to them, so my testimonial can be trusted. For my trans, my ring gear was part of (welded to) the converter. Unfortunately they only had converters for a v8 and I had an inline 6. I sent them my old beat converter with a bad ring gear. They removed to old ring gear, welded on a new one, and cut open and reworked the converter for my custom stall requirements, all for "free".
Hope this helps.
-Jim
http://cgi.ebay.com/ebaymotors/GM-TH...mZ150204155170
I bought a built c4 auto for my turbo 63 falcon from them, and I am 1001% satisfied. They are very accomodating. I am sure they'll build whatever you want. This TH350 is rated for 500hp and comes loaded with track goodies including a custom stalled converter.
I have absolutely no connection to them, so my testimonial can be trusted. For my trans, my ring gear was part of (welded to) the converter. Unfortunately they only had converters for a v8 and I had an inline 6. I sent them my old beat converter with a bad ring gear. They removed to old ring gear, welded on a new one, and cut open and reworked the converter for my custom stall requirements, all for "free".
Hope this helps.
-Jim
Le Mans Master
Joined: Apr 2005
Posts: 6,359
Likes: 428
From: Seattle Area WA
You can do a 4 speed swap for around that price as well. You'll need the pedal assembly, linkage, new console plate, shifter, used 4 speed, weld pivot bracket to frame, new flywheel, clutch assembly, new driveshaft and trans bracket to crossmember. It's nice with an auto crossmember because it's removable. Most of these parts can be found in a Corvette salvage yard.
Drifting
Joined: Apr 2006
Posts: 1,911
Likes: 2
From: gold coast queensland
i would just get another th350 . a streetfighter from b&m or the like and bolt it straight in with a stall of your choice then there is no modifications at all.just pull out the old and in with the new. prob at least a 2500 for that range of hp.if you do alot of hiway stuff then i agree with everyone else and choose another box but if you dont do much hi-way driving who needs a overdrive??? its a pain in the butt that you cant put an off the shelf stally in a 350 C.
Drifting
Joined: Aug 2007
Posts: 1,924
Likes: 6
You can do a 4 speed swap for around that price as well. You'll need the pedal assembly, linkage, new console plate, shifter, used 4 speed, weld pivot bracket to frame, new flywheel, clutch assembly, new driveshaft and trans bracket to crossmember. It's nice with an auto crossmember because it's removable. Most of these parts can be found in a Corvette salvage yard.
The pivot bracket for the Z rod is actually a bolt on for the 81. (corvette central) and the hole is already in your firewall for the clutch linkage rod.
I did this in 2007 (81 auto to 4 speed) using most parts from a 79. Best thing I ever did. It put the driving experience back into the Corvette. (something I always thought was lacking with the 3 speed auto)
Biggest problem you will run into if you want a stock shifter is the upright (bracket) for the shifter to mount to the 81 cross member.
There are after market shifters that will bolt directly into bosses on the trans (depending on the trans you use of course) or you can swap in a 78-79 cross member to use the easy to find upright for those.
Thread Starter
Instructor
Joined: Aug 2007
Posts: 116
Likes: 0
From: Temple TX
can anyone tell me the length of the tailshaft on the tranny for a 81 vette? Also, I heard you can not put 4.10s in the dana 44 diff and im wanting 4.10s. I wont settle for 3.73. Is this true? How can I tell what kind of diff I have on my car. Thanks!
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Thread Starter
Instructor
Joined: Aug 2007
Posts: 116
Likes: 0
From: Temple TX
Thanks for all the info guys. Just letting everyone know I purchased my parts. I got the TCI streetfighter TH350, with a TCI 2200 nitrious ready TC and some richmond 4.10 gears. It should all get here end of this week, I will take pics and post em up.
Drifting
Joined: Apr 2006
Posts: 1,911
Likes: 2
From: gold coast queensland
sounds like a good and simple set up. shouldnt have many headaches putting it all in. sounds like you definatly wont be hitting the hi-way with 4.10,s . i have a similar set up. turbo 350 b&m streetfighter with 3000 b &m stall. i running 3.55 gears and that is plenty low.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Just buy a "beefed up" THM350 that can handle the power of your engine. Leave the lockup feature intact...but put a toggle switch in the cabin if you want to defeat it. Just wire it into the "LU-ON" signal coming TO the lockup relay [not after the relay]. That way, whenever you want to "run" your car, you can turn OFF the lockup feature; and when you are on the highway, you can turn it ON.
