Transmission in 1980 vette
Thread Starter
Instructor
Joined: Jan 2011
Posts: 102
Likes: 1
From: St. Jacob IL
Transmission in 1980 vette
I have a 1980 with an L82 engine. I am having the engine rebuilt and it should be around 375 horse when I get it back. While I have the car all apart I am thinking about swapping the transmission from the TH350 to an overdrive transmission. I have a 700r4 but I am considering selling it and my TH350 and buying a 200r4 (2004r?) because I have heard that these are significantly easier swaps. Is this true? Also, would the 200 stand up to the power from the new engine or would I be looking at a blown up trans?
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
Search the forum. There are several articles about the swap you are considering. Basically, the 200r4 is almost a bolt in swap but required a special throttle cable to control trans hydraulic pressure. Certain models and applications of the trans are more desirable than others. It is a good swap that I am also considering as time and money permit.
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
2004R 1st-2nd gear drop is also not as severe as 700R4. That being said, I went with the Bow-Tie Overdrives 'Stage 2' 700R4 as it appears to have more, higher-horsepower options. Once I dialed in my combination, the 1-2 transition is not an issue. I get greater acceleration off the line than the equivalent 2004R and my trans should last longer and take more abuse.
Both have the TVS cable that controls line pressure.
I'd study what Bow-Tie's website has to say about the 700R4 and 2004R as conversions.
Dialing the 700R4 in for your speedo calibration imay be easier with the tailshaft cover removal (to pull the drive gear off tail shaft). 2004r requires pan to be dropped.
http://www.chevelles.com/forums/showthread.php?t=367847
http://www.bowtieoverdrives.com/index.shtml
Both have the TVS cable that controls line pressure.
I'd study what Bow-Tie's website has to say about the 700R4 and 2004R as conversions.
Dialing the 700R4 in for your speedo calibration imay be easier with the tailshaft cover removal (to pull the drive gear off tail shaft). 2004r requires pan to be dropped.
http://www.chevelles.com/forums/showthread.php?t=367847
http://www.bowtieoverdrives.com/index.shtml
Last edited by TedH; Jan 17, 2013 at 05:42 AM.
Thread Starter
Instructor
Joined: Jan 2011
Posts: 102
Likes: 1
From: St. Jacob IL
To be honest, budget is a concern. That's the reasoning for the 200 idea. I am getting my engine done for a really great price because one of my college friends knows the builder personally. I have a clean 700r4 right now but I have been having trouble finding a driveshaft or a shop that will make one. I have looked at the BTO site but I honestly think their stuff is a bit steep. If I remember correctly they charge close to $200 just for the crossmember. I would like to source parts (crossmember and driveshaft) from a 1982 but I can't find anybody parting out an 82.
Safety Car
Joined: Jan 2009
Posts: 4,000
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From: New York
To be honest, budget is a concern. That's the reasoning for the 200 idea. I am getting my engine done for a really great price because one of my college friends knows the builder personally. I have a clean 700r4 right now but I have been having trouble finding a driveshaft or a shop that will make one. I have looked at the BTO site but I honestly think their stuff is a bit steep. If I remember correctly they charge close to $200 just for the crossmember. I would like to source parts (crossmember and driveshaft) from a 1982 but I can't find anybody parting out an 82.
The BTO cross member makes the swap a dream and the 200 is a good deal once you do get a price on an 82 cross member ...
Next you dont want a drive shaft you want yours cut , to get it cut find in your area a tractor trailer break and parts out let. They will cut and balance your shaft with new joints cheaper then you will find a 1982 drive shaft.
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
The BTO cross member makes the swap a dream and the 200 is a good deal once you do get a price on an 82 cross member ...
Next you dont want a drive shaft you want yours cut , to get it cut find in your area a tractor trailer break and parts out let. They will cut and balance your shaft with new joints cheaper then you will find a 1982 drive shaft.
Next you dont want a drive shaft you want yours cut , to get it cut find in your area a tractor trailer break and parts out let. They will cut and balance your shaft with new joints cheaper then you will find a 1982 drive shaft.
Yes, an '82 crossmember is hard to find but having the custom crossmember meant getting trans mounted and in place a non-issue. It mounts to the same frame bolt holes as the TH350.
This was back in 2000 so quality control has improved I am sure. BTO located the e-brake pully bracket on the crossmember in the wrong place; I had to clearance the floor and then e-brake never was 'right'. When I had Van Steel rebuild my rear trailing arms, I had them grind the brackets off the crossmember and put them where they needed to be for proper e-brake operation. Issue solved (but my floor clearancing means I have a hole in the metal of my vette's floor below the driver's seat).
Safety Car
Joined: Nov 2008
Posts: 3,729
Likes: 559
From: Seattle Washington
I did this swap on my 80 back in 1987 or so. It really changes the was the car drives for the better. Since you all ready have a 700 it sounds like an easy choice. I modified my stock crossmember, there were no aftermarket ones back then. If I remember right the 700 mount if further forward and I just made an exstension plate. The stock Shifter works fine except you can't manualy shift down to 1st gear, but I never figured out why one would want to, the trans starts out in 1st on its own. The 82 uses a Dipstick Tube of its own, and I was able to buy one then wich probably isn't an option now. However the aftermarket has many options now, and I sure there is a GM one that will work. I doubt that a Driveline shop can redo yours for much less than $200 its just the cost of doing it. I later switched to a TKO 600 5 speed, and the drive line was the right length from the 700.
