**Overdrive auto info for those looking to do a trans swap**

Hey Phil,

Did you use the stock pressure switch and lockup solenoid from the BRF? I couldn't get mine to lcokup properly and bought a new switch and solenoid for a non-computer trans, but have not installed it yet. Too many wires on the BRF switch.

What size tire are you running and what speedo gear? You have the same combe as mine, but my RPM seems lower, about 2400, and I'm using a 235/60-15 tire.

Thanks,
Brian

 

I did not use the original pressure switch. I have pictures of the wiring we did. I think I only have 2 wires now. However I am not able to access them at the moment. Maybe tommorrow I will post. I trigger my lock up via a toggle switch.

I need to change it. It is for a 342. So I have some deviation but the cars I had convoyed with were doing 70mph.

 

I did the swap. Running 3.23 posi trac with 27 inch of tires. Using B&M dial in with with speed sensor set to lock up at 45 MPH as per instructions supplied. I have a vaccum switch on order, that has a closed circuit, it will open from 6 inch hg to 13 inch hg. So disengage lock up at WOT. I will check what the RPM is at 70 mph next time I am out. I am not running an external cooler but should...keep getting paranoid about it running too hot and causing damage.

My heads up would be for the geometry at the throttle linkage. The start, end and sweep of the TV cable at the throttle linkage plate from stop to WOT is very important. I was not happy with shift points etc. Big difference since i installed throttle linkage plate from TCI. (I have a e brock carb geometry ends being inaccurate if you just hook up TV cable at same spot as old ST 300 position.) I never seen so many warnings about inaccuarte set up will cause trani burn out. Set up on this unit is crucial.

PS I had looked into going to 3.93 or 4.11 gears...was cost prohibitive on the Skylark diffs...

1700 rpm at 55 mph. 2100 RPM at 70 MPH .

 

Going back into the axle ratio issue, what was an average ratio then for all those Park Avenues, Electras, LeSabres, Regals, etc, etc that came factory with the 200-4R? Am I going to crawl under potential trans donor cars and consistently find 3.xx gears? (and 7.5 r&p's?)

What about Caprices? Did they use 200-4R's or the 700-R4?

As for rearends that would fit my 67, '65's are a direct fit correct?

 

I think the Caprice had the 700r4....? Only the Monte SS had the 200r4 and I believe it had the 3.42 rear. 700r4 has less overdrive than the 200r4 (I think .75 vs .67....?)

The '67 rear diff had a different spring perch than '64-66, but could be used if modified, or I think you could use the early springs.

Brian

 

Oh yeah, now that you say that I remember... been too long since I've been under the '65 (got long-term backburner'd). Swapping a perch is easy enough.

 

Just to kick in another 2 cents here on the gear ratio and slippage issue...
As far as 83Stage1's question about how the luxo. 80s models (Electras, Rivieras, etc) with 2004r trannys did it, that's a good question. I'm guessing they must have used converters with very low stall speeds (like 1500 or so), and/or they had one of those speed selector switches that were mentioned above.
Regarding how those switches operate, can anyone out there elaborate? My understanding about how a torque converter works is that unless the rpms reach the stall speed there will be slippage (= increased heat and shorter life for the tranny). How could the speed selector switch mentioned above alter the speed at which lockup occurs? Or, am I missing something here in my understanding of the principles of torque converters?
I'm trying to weigh all of the options and opinions myself and decide if an O/D trans. is the answer, or just a TH350 or 400 with maybe a steeper 1st gear, and keep my highway rear gears.

 

"My understanding about how a torque converter works is that unless the rpms reach the stall speed there will be slippage (= increased heat and shorter life for the tranny). How could the speed selector switch mentioned above alter the speed at which lockup occurs?"

You're right on how the converter is working as far as the older non-lockup converters like a standard-issue TH350/TH400 works. With those there is no true "lock-up" tho, just a point where they're close based on how the hydraulics are working in the converter.

With a true lock-up converter like those used in the TH350C and the overdrives we've been discussing, there is a built-in electrical circuit in the trans that activates a truer lockup effect. The speed selector that's been discussed allows you to dial in when that circuit is activated/deactivated.

 

Greg-
Which rag ran the article on the trans swap? I would like to search their achieves to see if this article is posted online.

Thanks.

 

There is a scan of the article here: http://www.v8buick.com/showthread.php?t=68575&highlight=hot+rod

I have not been able to find an archive copy on their website.

 

I am runnig a 2.41 behind a 700r4 with no problem after 50000 mi. It can handle low rpm.

Its in a 81 granprix with a 6.2 truck diesel. city 26 hwy 34.

My Buick 350 is a race car.
Dan

 

Yep, that's the article. Thanks Joe

 

Where do you find the linkage for doing the TV set up on a buick carb? I have a 64 Skylark 300 with a 4GC and I can't find anything "easy" and bolt-on.

 

How easy was the 6.2 Diesel swap into the car?

 

Great idea to cruise around on the street, but good tires, dragstrip and BBB torque will make quick work of one of these transmissions. NHRA Stock and Super Stock racers run these or the 200 because of weight and gearing, but they spend big bucks and constantly maintain them. For your stock or mild 340-350 or V6 Buick fine or if you drive like your granny, great, but sticky tires and big torque will kill them quick. If you have one in a GS BBB and are not breaking it, you are drving careful, or have no power or traction. I don't want to be a wet blanket here but just stating the facts. It can be done with big bucks and constant replacement. I have talked to several companys and no one wants to put one in my car and stand behind it.
Jim N.

 

I agree commpletely, that why I'm using a th-400 in my truck...

 

Thanks Jim...that is why I am keeping the Th400 in the Jeep where brute strength and torque is primary goal and I'm using the 200 4R in the convertable.

Sean what truck is your workhorse?

Wayne S

 

It is a 81 Silverado, gloss black, reg cab long box,

Its off the rd getting a the Buick 350 from my 73 Century (35,000 miles) and a fresh built up th-400 with 2500 stall.I have no time so I'm paying a freind to do it for me. The torquey Buick 350 should be a good match for the 4:11 gears and 33" tires, and if you have seen/heard the 73 vvideos you know this engine has some JAM. I'm hoping that the Hooker headers will fit without much hassle but we will see....
http://www.v8buick.com/showthread.php?t=149233&highlight=bigger+toy

 

I started out with the 200r4 in the 81 GranPrix behind the 6.2 . It worked ok until it shucked one of the splines after I ran it though the gears on the mat. Man does this thing blow the smoke when you mat it. I then put in the 700r4 that is used in the diesel pickup truck. No problem after 50,000 miles.

PS I gave the 200r4 away.

Dan

 

Good point. The 200R4 needs big $ upgreades to standup to big torque