Anyone do this swap? Seems like it should be pretty easy since they say 2004R will bolt up where TH350 formerly existed? I know late C3's came with 700R4's but the 2004R can be built for more power/reliability and the gear ratio's are slightly more appealing! Any info?

 

up until 79 it is a direct bolt in, i am doing mine now. after 79 i believe the crossmember changed requiring you buy one from someone like bowtie overdrive.

 

www.2004r.com

this is the website for bowtie overdrives, i will be doing a700r4 swap in a couple of weeks, just got most of the parts last week, just waiting for weather to get a little colder to do the engine/trans swap.

 

I got my setup from BTO. 2 years without any problems. I drive my car everywhere including to Bowling Green, Ky for NCM Labor Day festivities. I went from 11mpg to 17mpg, cruising at 2200rpm's at 70mpg.

200 4R

 

Fitted a BTO 200-4r (level 2) in my '81. Should be the same installation as an '80. Highly recommend the TV Made EZ kit & their shifter conversion. Used a 2200 stall converter & am very happy with the entire conversion. Beyond happy
You WILL need the BTO x-member for the swap. I tried to do the conversion intending to modify the existing x-member (being on a budget), but there was no way to modify the std one (the work involved would be more than making a custom one myself). The BTO x-member is a great fit, the trans is positioned perfertly & the x-member is shaped so that true duals can easily be fitted. The paint on the x-member is rubbish, so get it powder coated prior to starting the conversion. No mods needed to the driveshaft (recommend changing the UJ's though, while you're at it!). Somewhere in the archives is a post I wrote about the swap (200-4r installation, lessons learned - or something like that).

 

Ukpaul, With the bowtie crossmember were you able to run your true duals on both sides of the transmission or did you still go on the passenger side like most people do? Also, what headers are you running?


-Justin

 

Hi Justin,
I fitted Dynomax ceramic coated headers (1 5/8" - 3") with 3" - 2 1/2" reducers, one of which has a fitting for the O2 sensor (all from Summit). The 2 1/2" pipes run down each side of the car The only snag is that the drivers pipe runs under the floorpan which, as you know, is lower than the p.side floor pan. This gives 3" of ground clearance under the drivers side pipe, the lowest part of the system being right under where I sit. I'm very aware of it when it grounds out! Stronger front springs will probably prevent the grounding out which only happens on one particularly bumpy road at over 70mph.

I made the system myself, getting a local pipe benders to supply & bend the satin finish st/st pipe, using a former that they make F1 racing systems with. Got some lovely bends with no crimping. I made each side out of 3 separate pieces. The 1st piece fits to the collector and has a 15* bend in it to bring the pipe up to run level under the car (the headers point slightly down). The next piece is a short length that I welded about 4" of pipe onto the side of & cut out the inside to form the "H" pipe (cutting & filing the metal out was a real pain, but not the worst part of the job). A straight length of pipe was run between the 2 sides to form the "H". The final piece of pipe runs down to the rear of the car, passing to the side of the diff in the gap by the inner end of the rear strut. Just after this point I had an 85* bend made & the pipe then kicks outwards & slightly up (as the originals did) to mate up with the muffler. Each side is a mirror image of the other.

I made each length of pipe slightly longer than it needed to be so that I could juggle the whole lot about to get the best fit. To joint the pipes I bought a SnapOn pipe expander. What a nightmare. Cutting & filing out the pipes for the "H" seemed like a holiday in the sun compared to expanding the pipe ends. What a job, it took me 2 weeks of mornings, lunchtimes, evenings & weekends to expand 6 ends!!! I was living proof that the Brits use the worse language in the world, frustration at wasting 2 weeks & $100 on a tool that didn't work pushed me over the edge of normal rational behaviour Hint 1: use thin walled st/st pipe. Or use steel for an easier job & a better sound (st/st tends to sound a bit tinny). The tool would tighten until I could feel the tube starting to expand, but at the same time I could feel the bolt in the tool about to strip its thread. It took me 13 high tensile bolts to get the job done. If the SnapOn tool had used bolts of 5/8" diameter (or more) then I've no doubt that the job would have been a lot easier, but the tool is supplied with a puny 9/16" UNF bolt. No wonder it stripped repeatedly (the thread in the tool survived unscathed after a total of 14 bolts had stripped). 18 months later I'm still waiting for the SnapOn guarantee of replacing faulty tools to be carried out. Am I pissed off with SnapOn? You bet! For this reason, if I was to do it again, I'd get a pipe shop to expand the pipe ends. Once you've expanded the pipe ends (good luck!) then clamp them together using normal exhaust clamps (no need to slot the expanded ends), but ensure that the clamps are positioned so that the threaded ends don't point down as that would really reduce ground clearance. By using a male/female fit to join the pipes together you'll get a small amount of adjustment in the joints for fine tuning the positioning of the system.
The Headers ably support the front of the system & the stock muffler hangers support the rear. That would probably be adequate, but for a belt & braces approach I went down the local exhaust shop & got a couple of standard rubber straps used on many modern import cars. These straps have long metal hooks on each end. Use large hose clips to clamp the end of one hook to the upper edge of the pipe & open out the other end enough for a 5/16" bolt to go through it. Somewhere under the car will be some bolts (forget where) that are almost above the new system on both sides of the car (may be bolts to hold brake lines to the x-member???). These bolts are ideal for fixing the straps to the underside of the car. Do not fit the straps under any sort of tension as they will snap. Just take up all the slack & tighten the hose clamps.
The "H" pipe is positioned just rear of the trans x-member &, by fitting it to short stubs welded to each side of the exhaust pipe, it should be easy to remove without having to dismantle the entire system (for access to the driveshaft).
Getting the mufflers to sit correctly at the rear (both level, both pointing directly back & level with each other) was an exercise in futility! Just get them about right, drive around for a while & then level them up. For some reason mine tended to move about after the 1st few drives (probably due to the high expansion rate of stainless), but it eventually settled down & now the mufflers stay lined up OK. The "H" pipe was worth fitting as it keeps the entire system rigid & it mellows out the harsh sound true duals give. Unless you like the sound of an all out artillery barrage behind you, I wouldn't recommend fitting the glasspack Monza style mufflers ("loud" is an understatement!).
I'm convinced that the Dynomax Headers & this new system have reduced cabin temps & I've had no problems with having the O2 sensor mounted further away from the exhaust ports (I used copper gaskets for the Header to Head joint & threw away the supplied bolts, opting for some allen head stainless set screws instead. The allen heads were slightly longer than the supplied bolts and were fitted with a st/st spring washer under each one. I did them up mega tight with my "special" allen key & haven't had any problems with them at all).

I've got a picture somewhere I can email you if you'd like to see the finished system. Unfortunately I took it during the last annual inspection - if I'd taken it after fitting them you'd see the fruits of my labour in polishing the pipes (I've got some obsession about polishing st/st!) & cleaning/painting the underside of the car. During the inspection I discovered that there's an engine oil leak & my beautiful gleaming exhaust system is now covered in burnt oil & general road clag
-------------------------

Apologies for hijacking this thread, but you'll probably do what I did after fitting the BTO x-member and, while lying underneath, think "Oh gosh (or something like that), I can fit proper dual pipes now" & before you know it everything will snowball on you. Then you might find that your new system decks out at speed on large bumps, so you'll then need stronger springs..... does it ever end?

 

Thanks for the reply guys!

 

sounds like a good area for the oval pipe to be used

 

Thanks for the info guys you really helped me out I ordered my 2004R yesterday with the info you provided.
Thanks again!

 

I know you already ordered, but the thread below has some interesting info on 200R4 vs 700R4. From what I read, your rear end ratio will determine which one you should choose.

http://forums.corvetteforum.com/showthread.php?t=389531

 

Thanks for the link even after looking at it I feel I made the right decision I'm going with 373 gears so the 2004R should be the right choice plus I like the lower rpms at cruise.

 

I have 3.90s in mine and the 2004R is on the list of projects for next spring! Getting 7mpg now so it should pay for itself quick!!!

 

I went from 10-11mpg on the highway to about 16-17mpg. Thats with 2004R and 3.55 gears.

 

Don't you have to change to a 400 crossmember in a car that had a 350?

 

I'm not sure what crossmember you need but you do have to change it, it was 40 bucks from BO, and tranny should bolt right up.