NeverDoneC3

I need help deciding what transmission to use. I have an 80 with engine mods and 3.73 gears. I currently use a 3000 stall with a th350. rpm's are to high for highway use but i love the gears. I'm looking for the best set up and would like to hear the pros and cons for each tranny. I'm also interested in hearing what modifications are needed for each. Any help will be greatly appreciated.

BigBadRed

Do a search, there is tons of stuff here. I believe the 2004ris the direct bolt in with no mods.

American Boy

I'm looking for an overdrive transmission too and here's what I found.

The 700R4 are more suitable for rear end ratio under 3.36 because of the 1st gear that is 3.xx. The drop bethween the 1 and 2nd gear is also noticeable. You have to change or fabricate a crossmember and cut the drive-shaft.

The 2004R like rear end ratio like 3.55, 3.73 or even 4.10. The gear ratio are evenly spread out. You have a 0,67 overdrive too (700r4 have 0.70). The crossmember have to be change or relocated (unless you have a TH400)(not in an 1980). Driveshaft is the same lenght.

A stock 2004R is not made to take abuse with 350 hp and up engine. The bowtie overdrive unit at http://www.bowtieoverdrives.com look like the best option as cost unless you modify your tansmission yourself.

Stephan


[Modified by American Boy, 11:15 AM 3/17/2004]

gerry72

If you keep the 3.73s then you'd want to look at the 2004R (the 200R4 is a very different trans and you really don't want to even make that mistake) since it has a 1st gear ratio more complimentary to your existing rear gear(2.60 or so as I recall). The 700R4 has a very steep first gear (like 3.10) and will give you a granny first gear.

The 200 is closer to a direct bolt-in and requires fewer fabrications and modifications. Go to bowtie overdrives or search the web for conversions to get a good idea of what's involved and what the various kits include.

PatsLs1vette

the 200r4 is easier to do,the 700r4 has a lower first gear in them,i have 3.70 and i love the low first gear but some others dont.I had to cut my driveshaft and modify the crossmember also.Youre probably better off with the 200r4.

Buffalo Dude

I've been told the 2004r should bolt into where a TH400 was, but the driveshaft needs to be shortened. On a Th350, the driveshaft should stay the same, but the crossmember may need to be moved. You'll also have to go to a 27 spline yoke, I think 350s have it but 400s don't. I would go 2004r, I've heard nothing but good things about it. I'm sure the 700r4 is good also, but some have had problems with it. I'm also considering the 2004r swap for my th400 and I'm starting to lean toward BTO. I'm going to check out their stuff in june, so I'll post what I find for those interested.

redwingvette

"I've been told the 2004r should bolt into where a TH400 was, but the driveshaft needs to be shortened."
Not so on mine. Drive shaft was untouched. The front universal had to be changed to attach the 27 spline yoke but with stock GM parts at any auto parts store.
http://hometown.aol.com/bmclau5079/page4.html

UKPaul

I fitted a 200-4r (BTO level 2) in my '81 which, I believe, is about the same as the '80. The driveshaft didn't need any mods, their TV Made EZ kit sorts out the TV cable geometry & allows you to decide (& alter) the shift firmness, their shifter conversion kit (for the extra gear) is easy to install & looks like it came from the factory when done & the x-member WILL need changing. I tried to get by with altering the stock one but it was such a major job that I gave up & bought the Bowtie one (& the shipping charges were more than the x-member!!!!). The Bowtie x-member is excellent as it allows you to run true duals. My rear end ratio is 2.87:1, which is to high for the 200-4r apparently (recommended 3.55 or more), but it drives just fine. It's the best mod I've done to the Vette & transforms it :)
Recommend getting the Bowtie pressure guage for setting up the TV cable adjustment, a tranny temp sensor & guage & also to fit a SMALL transmission cooler.
:cheers:

John Dirks

NeverDoneC3,
Call Art Carr personallyat
California Performance Transmission.
1-800-278-2277
Tell him John from Canada told you to call him.
If you want the best transmission available,
Art will personally take care of you.
He is building me a 200R4 for me right now for my highly modified 76 Vette.