To the guys out there that have experience with this conversion I have some questions.

I am gonna install my own 2004r in place of the th350 in my 80 L48... first time doing it myself. I do little without tons of research first, highly mechanically inclined in the collision industry for 38 years teaching in collision, body, paint, suspension, fabrication, welding etc but driveline is not my wheelhouse beyond the normal stuff.

I have a stock configuration 1980 with a rebuilt 2004r ready to go, ordered a new 2000ss converter, adjustable TV cable, correct bracket for the Qjet... this 2004r came with braided flex dip stick/fill tube appropriate for the deeper pan, I also have the B&M lock up controller (Speed)

I have researched enough to know what this will entail as far as difficulties in removing driveshaft and TH350 but I have a few questions again for those who have done this swap especially later C3 as I read some discrepancies.

* it looks like I will need a modified crossmemeber, appears 79 and older are OK but 80/81 crossmemeber will not work with the 2004r... is this correct and best source? Or find a 79 and older?

* are the transmission lines the same configuration, i know the location is slightly different but im reading the top and bottom lines are inverted between the two transmissions.

* is there a linkage bracket available for the 2004r pan bolt pattern, as i remeber from long ago one of the two bolts lines up for correct linkage but not the other.

* I plan on removing the distributor cap and fan before I begin... will the top two bellhousing bolts be easier from the top side or under with trans/engine tilted back a bit and long extension?

* how much forward/back movement am I looking for with the torque converter to flex plate before considering washers between the two or does it matter?

* If using the B&M controller where did you mount it?

Thanks in advance

 

I plan on doing the same in my 80 L82. I did this swap in a 78 Trans Am years ago with a 200r4 from a wrecked Buick Grand National. Was very easy on that car.

 

I did this on a number of camaros and later C3s back in the 90s but clearly my memory isn't too clear, i definitely dont remember changing crossmembers but appears I will need that with the 80, Vivid Racing looks like they have what I need for a crossmember.

 

Golfobsessed
I did a 200-4r in my 68 in 2022. I was going from a manual so a little different so yours should be slightly easier. My responses will be in this BLUE color so you can see them easier.

 

Golfobsessed
Not mine but this is how this fellow modifiy the lower shifter bracket for his Turbo-350 which would more applicable to you than the mod I did to the turbo 400 bracket:

https://www.corvetteforum.com/forums...post1585524977

and just fyi here is how I modified my Turbo-400 lower bracket. Drilled a bigger "indent" and rebent it. https://www.corvetteforum.com/forums...post1604903026

And here you can see where I notched the detent plate with a dremel. Easy peasy and I was overthinking it. https://www.corvetteforum.com/forums...post1604916531

 

Golfobsessed
Found this info about installing and bolting down my torque converter (TC). YOu need to absolutely make sure that the TC is fully inserted onto the tranny. You bolt up the 200-4R to the engine. You should then have about 1/4" between the TC mounting pads and the flexplate surface (anyway, I did). You then just snug it up to within 1/8" to 3/16" inch gap using flat-washers. You can use a 1/8" drill bit to check for that gap value. Then locktite it and torque the bolts down.

If you do FB you can go join the 200-4R Nerds group. I should have joined before I started -- I ended getting lots of pointers there (gotta filter the bs as appropriate).... https://www.facebook.com/groups/2195342030751087

 

thanks carriljc, this was all very helpful, i found a crossmember (Gforce) at Vivid with the parking brake roller bracket attached. Thank you again

 

I did the swap in my 76. I got my crossmember thru www.bowtieoverdrives.com

 

You don’t need the B&M lock up kit because your car already has it from the factory

 

thank you, I ordered the GForce through Vivid Racing, wanted one with the parking brake bracket and thought this was a good price

 

how will my car being a 1980 control lock up in forth gear with the 2004R

 

because your 1980 has a T350C (C= TCC) has a lockup already that just needs hooked up to the 200R4 . I have two 1980 L82’s , one is converted to a 700R4 and the other I might go 200R4 so I don’t have to modify the exhaust

 

OK when you say "hooked up" hooked up to what, this is not a computer car so I would still have to buy a vacuum control kit no?

What is it your hooking up to the 2004R from the 1980 corvette as there is not a vacuum control on the 2004R

 

Yep , no computer needed your car already has the TCC vacuum switch mounted on the fire wall between the brake booster and wiper motor with a harness that goes to your T350C transmission and the correct brake switch that releases the TCC and stops cruise control with a tap of the brakes , all you have to do is change the wires to the 200R4 connector at the transmission

 

I wasn't aware of this, thought that was 1981 and my car needed some kind of controller be it speed or vacuum, thank you
gathering all my parts now and not gonna start till I return from vacation Nov 2nd.

 

Your car has a factory TCC aka Lockup Torque Converter. It uses a temperature controlled vacuum switch next to the thermostat housing that also that feeds vacuum to the EGR Valve , TCC vacuum switch and Cannister Purge Valve . Once engine is warmed up the vacuum switch will activate the TCC in high gear as long as the vacuum is between 7 inches to 3 inches and the foot brake is not activated. Works great too and NO computer . 81 and 82 uses the computer but you are in luck

 

this is really good to know, doing some research on it now... thank you again Eric

 

Just a FYI on that crossmember, it WILL fit the 1982 C3 as well perfectly, but you can not use the stock exhaust with the CAT with it. If you go true duels all the way back then you can use that member. I have run it on my 82 for a long tie now.

 

thanks Buccaneer, i have a brand new Corvette Central single side true dual no cat magnaflow exhaust but just recently removed for Dougs headers and side pipes.
I was planning on modifying the new Gforce crossmember before I install it for the single side dual in case I ever wanted to go back but after looking at your photo there may be enough room for the both pipes to one side.

 

I am running a 4L60E in my 81 using the G-Force crossmember. You can run true dual exhaust system but you do have to run it down the passengers side under the seat. Here is how I did mine. There is enough room to run it through the crossmember and make the turn before getting to the drivers side floor pan.