Okay.

So, quick update. A year ago, I'd never worked on a car before, never picked up a wrench, had no idea about how anything under the hood worked. Since then I've acquired a '77 L48 with everything horribly broken, a lot of parts, tools, and good advice, and have been having fun.

Part of the fun has been putting in a new gas tank and building a nice new engine for the thing, which is pretty much ready to go as soon as I bolt on the manifold. Without boring anyone about the exact specs, it's supposed to produce something in the range of 400-420hp, which will almost certainly cause the badly-abused stock TH-350 to explode in a puff of smoke by the time it reaches the end of the driveway.

I need a new transmission, and as I'm already about twelve thousand dollars into a car that's going be worth maybe five thousand when I'm all done, I might as well throw caution to the wind and do the job right.

I've done some reading, and it's looking like the 2004R or 7004R are the way to go. It's an auto, and I don't want to convert it to manual (because then my wife can't drive it and I'll never hear the end of it). Apart from narrowing it down to one of those two, I really have no idea what else I need to know to make the right decisions. What torque converter should I be thinking about? Any way I could just go and find something that'll bolt in place of the original tranny (and thus be something I could do myself with beer, basic tools, and a weekend)?

I don't need the 'vette to be some complete monster off the line. I'd just like to be able to drive the thing without worrying something is going to explode...


Help.

 

i think either one of these places can answer your questions, and the 200r4 would probably be the easier swap due to its size relationship to the th350


http://www.phoenixtransmission.com/html/gmtrans.html

http://www.2004r.com/faq/faq.shtml

 

I have 1980 L48 auto- I put in a 200R4 from BowTieOverdrives. It was straight forward and required no special tools. I had never swapped a trans before.

Darrel1

 

I've read mixed reports about what these things are rated to work with; my new and improved engine is going to be somewhere around the 400hp area - I'm just concerned that a stock 2004R may not handle the load.

Encouraging to hear that it can be done fairly easily, though

 

Bowtie overdrives also offers the 700r4.. They also have different levels of trannies to better accomodate the level of HP your engine is producing.

 

I sent you some good info I got from mdbelanger when I was thinking of doing this to my 77...

I wound up changing the gears in the rear end and getting my th400 fixed.. no more leaking... But my motor was only putting out 320-350hp on the dyno..

Good Luck!

 

There are several builders that offer 200-4Rs built to handle your level of HP. Bowtie Overdrives is one of them. I'll be swapping mine later this year and plan to go to a 200-4R built to handle at least 450 HP.

Good luck with it. Let us know what you end up doing and how it goes.



DC

 

I just ordered a BTO 200 4R Stage 2 with 2200 RPM converter- for my 80 with a rebuilt 355. BTO had a sale last week, with $350 off. It should be delivered tomorrow. I'm hoping for the deeper 1st gear, firm shifts, and the low RPM'sof the .67 overdrive.

 

The overdrive is awesome. It took some time for me to properly adjust the TV cable. Mine was shifting gears way too early and causing the vehicle to hesitate/bogg. now I have it adjusted properly.

The one thing I like about BTO is the Tech help. I called them several times and they were more than happy to help.

Darrel1

 

200R4 is used behind some very NASTY Buick V6 turbos if it is properly built it will handle any sane amount of HP. Here is a link for one of the better builders: http://www.cpttransmission.com/index.htm

 

Bowtie seems popular here.

http://www.bowtieoverdrives.com/cata...SUBCAT&CATID=C

Keisler makes a nice auto trans for the C3

http://www.keislerauto.com/index.php...550-lb-ft.html

I don't know anything about Gearstar but they sell auto trans as well.

http://www.gearstar.net/transmission...ls.php?unid=60

 

What gear and engine hp did you have with the 2004r install. What gear would you use if you could choose any gear. Same? DIfferent?

I have to make up my mind on gears soon. Getting ready to put mine together....with a ZZ4 engine.

Thanks and best regards...Stan M.

 

Stan,

Please check out this new feature on our A-41 4-speed automatic in Popular Hot Rodding:
http://www.keislerauto.com/index.php...09/Page-3.html
or link here

 

If you really want to get all you can out of your engine when coming 'off the line', you will also need to upgrade your rear suspension system and rear tire set plus install higher stall speed [and stronger] converter on whatever tranny you buy. But, if you just want a powerful 'driver' vehicle which is road-friendly to drive, you probably want to go with a 200-R4 [overdrive] tranny with around a 2000 rpm stall converter on it. Basically, it boils down to whether you want a 'drag' car or a well-powered 'driver' car. Given your discussion of your wife's occassional use of the car, the latter choice probably makes more sense [and is considerably less expensive]. Besides, once you do all the stuff in the rear end to make it capable of super-duper starts, you'll find that 400-420 HP is underpowered to many other similarly built cars.

Stick a sturdy 200-R4 in it with decent sized street tires on the back and have fun!