Guys,

looking to swap out the TH350 in my 1978 Pace Car with a 2004-R kit from Bowtie Overdrives.

Had a long chat with them and they can supply pretty much everything I need.

The engine is stock and I'm looking at their Stage 1 transmission

Of the guys who have done this, I like to hear:
1. How "bolt in" is it really? and how long should the swap take?
2. What stall speed did you use and why? (I'm looking at the 1800 vs 2200)
3. Did you use the brake switch to "unlock" the converter and how does this work in terms of driving? Any issues/concerns?
4. Was the TV cable easy to fit/adjust?
5. Do I need their aftermarket crossmember if I have standard original exhausts?
6. How easy/hard is the shifter kit (SC2403) to fit?
7. Is there much to connecting the cable to the 2004-R and getting it right?

As I'm in australia, I'd hate to make a start on this then discover I'm missing a part/something - as you can't overnight to Down Under!

 

http://forums.corvetteforum.com/c3-t...ome-on-in.html

good place to start--

 

I'll give you a bump Im interested in this as well.

 

RIO68,

yes had seen that thread - and pretty much all of them, but there seems to be little in a detailed installation and/or driving experiences afterward.

BTW anyone know what the stock Stall speed is of a L82 with Th350 transmission.
some net sources suggest 2200 (can't be right) other sources suggest 1200....anyone?

 

When I had my 350 built trans man said somewhere in the 12-1300 range. I pulled it and he built a 700R4 and I installed it instead. I really like the driveability of the OD trans. Stall on this one is 2200 I believe. Lots of good/bad discussion on which OD trans to use (200 or 700). If you have a good rebuilder you can save money up frt by getting a used trans and having it rebuilt. Then get the other stuff for which ever one you decide to use and putting it in.

Adj. TV cable was my biggest issue but got it done. I opt. for the valve in the valve body that controls the lock up and did not use the electric control-seems to work fine.

 

Thanks for the reply.

Can you explain how the valve body works to lock-up the overdrive?

What are your driving impressions with the 2200 stall converter vs stock?
still trying to get my head around what difference this will make.

I have read the 200 vs 700 threads and obviously a lot of passion on both sides.

My reason for a 200 is that I'm keeping the engine stock and I don't need to modify the tailshaft.

any input is most welcome!

 

I swapped to a 200-4R this past winter. It's a bolt in because you keep the factory driveshaft, crossmember, and exhaust. It takes as long to put in as it does the TH350. I'm using a turbo Regal transmission with it's factory converter, but IDK the stall speed.
I'm using a TCI converter lockup kit that references a supplied overdrive pressure switch, the converter locks when the switch senses overdrive, and unlocks upon downshift. You have the option of adding a brake switch into the circuit.
I bought a Bowtie Overdrives stainless / braided steel TV cable "system". It works fine but none of the lasered holes were drill checked so I had to re-size them myself.
You can use the factory crossmember and keep the original single exhaust, just take off the TH350 extension and bolt the mount to the two remaining holes in the top. I checked the driveline angles before and after, they are within 1 degree. The Bowtie crossmember will give you all the room you could ever need for dual exhaust tho.
I didn't modify the shifter, P-R-N-D mesh perfectly between the trans. and existing shifter. Had to modify the shifter cable bracket on the transmission tho, moved the rear hole a bit, and the detents match.
You should check the line pressure to set the TV cable, easy enough to do and Bowtie can sell you a gage for $30. They have a good explanation on their web site.
I also added a transmission temperature gage and a pretty big auxilliary cooler as cheap insurance.
I can't tell any big difference between the 200-4R converter and the Holeshot that was in the TH350.

 

SH-60B,

Thanks so much for the input, really appreciate it.

Does the trans unlock in 4th, say when you come to a hill and you don't need to kickdown to 3rd or does it only stay in locked 4th or kickdown to 3rd?

I have a twin system running through the two holes in the crossmember, do you think I can retain it if I remove the TH350 extension?

 

Can you explain more about the valve. I was going to do the wiring when I switch to my 2004R bnut this sounds better. Any numbers or where to buy?

 

I did this swap in my 81. I had to modify the cross member, shift cable bracket, and wire the lock up. Other than that, it's a bolt in. The lock up feature is a selenoid that directs fluid pressure to the torque converter to engage a clutch inside converter itself providing a 1:1 coupling ratio with the engine. This selenoid is electrical and can be engaged several ways. The transmission have a pressure switch on the fourth gear circuit of the valve body that typically energizes the selenoid, and it's wired into the brake light switch as well to dissengage it when the brakes are used. You can also use an aftermarket controller to do this. Me, I wired a rocker switch into the system so I can choose when to engage the lock up. This works best for me, because I don't want it locked up all the time when the trans is in fourth gear depending on traffic situations, speed, road conditions and so fourth.

As for the stall of the converter, I'm at 1900, about what stock is on the TH350. I did this because I have 3:36 rear gears and a bunch of torque (I have a modified BB in the car) and would rather have the car moving rather than smoking tires. The 2800 stall converter I had was fun, I could sit and roast tires easily, but that doesn't get the car moving that quickly from a light....

 

[QUOTE=puzzigully;1577336401]SH-60B,

Thanks so much for the input, really appreciate it.

Does the trans unlock in 4th, say when you come to a hill and you don't need to kickdown to 3rd or does it only stay in locked 4th or kickdown to 3rd?
Good question. I'll let you know as soon as I've tested it out.I have a twin system running through the two holes in the crossmember, do you think I can retain it if I remove the TH350 extension? You'll probably need to re-work the left pipe. The back of the pan rail is very close to that side.

 

Don't know if the 200 4r operates the same. I got a line on it off a forum and asked the trans shop and they said it was available. I think cost was 65-75 or there about. Mine works better after it warms up, but it works fine. My car has cruise and connecting to the brake switch wasn't an option. For a slick operation the 4L60E with computer control is probably the best option--no TV cable or lock up concerns.

 

Thanks for the info.

 

I spoke to the guys at Bowtie overdrive about doing it this way and they do not suggest it as an effective way with the 2004R.

Still trying to work out what happens when you're in 4th (locked up) and then you come to a reasonable hill.
It is in this situation, you'd want it to unlock but stay in 4th and get an increase of 200-400 rpm so you can climb comfortably.
It seems to me it will:

• Lug up the hill until you press hard enough on the gas for it to kick down to 3rd OR
• You have to manually unlock it by hitting the brake, but it will lock up again almost immediately (not sure on how quickly it will lock though?) OR
• Install a manual switch that will prevent lock up and use that every time you need it to unlock in 4th - most likely forgetting to return the switch to allow lockup after the hill

Any comments?

 

I have been following this thread intently as I plan to upgrade from TH400 with a totally non functional kickdown and 3.08 rear, to a 200R4 with 3.73. My preference from your scenario would be for the TV system to interact with the pressure selenoid which controls the lockup. So the expectation would be that a properly tuned TV system should get you there, theoretically. However, in practical application it may be virtually impossible to get it to do exactly what you want. My 04 Avalanche with 4L65E slips the lockup every now and then, and it's supposed to be ECM controlled. I guess of course it could be EPA code.

Probably better plan on shifting down manually when the need is immediate.

 

I did the 2004r swap from a turbo 350. Easy swap. Make sure you get a dip stick tube also the stock one doesn't fit. I recommend using an electrical switch for the lockup. If you are worried about climbing hills in 4th don't be. I do just fine with it locked up. You don't really need to be in 4th for anything under 55 to 60 anyways it will just burn up your trans quicker.

 

Thanks for the input guys.

spoke to Chris at Bowtie and he confirmed that when the trans shifts to 4th, it is locked.
He feels going to "unlocked" 4th is a waste of time, as if you need extra grunt, dropping back to 3rd is what you want, not an extra 100rpm by going from locked 4th to unlocked 4th.

I did also ask, that while I will be cruising at 65mph, the engine will be running a tick over 1,900rpm - will I see slip from the Stall converter if it is a 2,200 version?
He confirmed that if I'm in 4th - it is locked, no matter what the rpm is. So the answer is No, even if it was a 3,000 Stall it would still be locked.

I was after a swap that would perform as close to a factory install as possible.

Looks like the 2004R ticks all the boxes.

 

Install an electro-vacuum switch switch that unlocks the tranny when vacuum drops. When you hit a hill (or go to pass somebody), the carb opens up and the vacuum goes towards zero, unlocking the tranny. When your foot comes off the gas, the carb butterfly closes, increasing vacuum, closing the switch and re-locking the tranny.

 

Yes, I was looking into that system, it seems not as straightforward as it sounds.

The big problem is getting the switch to activate at the right time - that is, at what vacuum pressure does it switch?
there are quite a few variables in that alone, even more complicated if you have camshafts that have increased overlap, thus reducing vacuum. (I don't)

It might be something to add on at a later date if it really does bother me I guess.

As a matter of interest, can you suggest a part number for that switch and where I would plumb it in the system if I was to go that route?

Thanks

 

I replaced my tH400 with the BTO 200-4r and love it. I did want a little more "hands-free" controll so I installed a B&M controller. The controller does not let the convertor lock until you are traveling more then 40mph and unlocks if you slow down even before the trans would downshift.
Before I installed the B&M controller I did experience some chugging/pinging when I would hit a hill or slow down before the trans downshifted. I could have solved the issue simply by downshifting the trans to 3rd myself but now I don't even have to think about it.