700r4 lockup

Pontiacparisienne85

New member
Dec 24, 2020
3
1
Hi everyone I have an 85 Parisienne wagon that I am upgrading to a sbc 350. As part of the upgrade I plan on removing the computer controls, I already have a non electronic Quadrajet and vacuum advance distributor to use but my question is about the lockup on the 700r4 trans. I'm trying to find out what feeds the signal to the trans to engage and disengage the lockup solenoid. My main question is does anyone have experience removing the computer and if the computer is removed will lockup continue to function as it did in stock form.
 

GoodOldsGuy

Member
Oct 20, 2020
41
8
Texas
Hi PP85,
You will definitely need to get a replacement system to engage the lockup solenoid on a 700R4 running without a computer. Without locking up the torque converter, the transmission will likely overheat and fail in an inappropriately short amount of time/miles. It could be as simple as a switch on the dash that YOU throw to control when the torque converter locks and unlocks. Just don’t forget to hit the switch when trying (and failing) to stop the car because it will add a level of difficulty that could easily cause an accident. Think stopping a manual shift car in gear without steeping on the clutch pedal. I’ve had a torque converter fail to unlock before (on a TH350C), trust me, it’s very disconcerting. There are several kits commercially available right here in the United States. They operate in several different ways, but most will automate the system enough to free you of concern over flipping a switch. A quick DuckDuckGo search will show you quite a few articles about the subject, with several different kits people used and how they work. Side note; A TH700R4 (and TH200-4R) use a throttle valve cable, NOT a kick down cable, and it needs to be adjusted correctly to keep from ruining the transmission. I highly recommend getting a kit. Now, what engine/transmission are you taking out that would qualify a carbureted SBC/700R4 conversion as an “upgrade”? The Oldsmobile 307/TH200-4R was a common application in 1985. If that’s what you have, you’ll need to move or replace the crossmember and have a driveshaft built for it as well. If you do have a TH200-4R, you already own the correct throttle valve (TV) cable and carb bracket to make a 700R4 work. TH200-4Rs came with a universal (GM) bell housing bolt pattern and will bolt right up to a SBC of the era, eliminating the crossmember/driveshaft conversion needed for a 700-R4. 700’s only came with Chevy bolt pattern housings. The 200-4R has a higher OD gear ratio than a 700R4, .67:1 vs .70:1, but it’s 1st gear was also higher, 2.74:1 vs 3.06:1 for a 700. 1985 Parisienne’s were not made of super ultralight weight “unattainium”, so I doubt you are looking for spectacular quarter mile times. If you are, I would recommend lifting the radiator cap, and sliding another car underneath it. But if you’re like me, and just want a super cool old B body to cruise around in that will get at least double digit gas mileage at 70mph, then 700-R4 vs 200-4R (both reasonably built) is a lateral argument. If you do have a 200-4R that’s not cratered, and want to give it away, put my name on the list :) Another side note, if you have a 307 Oldsmobile now, a 455 Oldsmobile big block will drop right in, AND bolt right up to everything you’ve got now, and will embarrass the SBC, and the 307 with upwards of 500ft/lbs of torque. Definitely upgrade the TH200-4R (and the radiator) to a very well built version if you go that route. I mean, if you’re getting rid of the computer, you might as well get rid of the rest of the efficiency too, and get some impressive torque numbers in the process. :)
 
Last edited:

Pontiacparisienne85

New member
Thread starter
Dec 24, 2020
3
1
Thanks for the info Goodoldsguy, the car is and early 85 before they made the switch to the olds 307/200-4r combo so it currently has a 700r4 in it which will be staying behind (for now) and I will be removing the current chevy 305 to upgrade to the 350. I do have a second 700r4 that I plan to rebuild and beef up a bit and install at a later date. My goal was to just have a nice cruiser with a bit more power, the 350 is baisically a stock build with an rv cam in it. I already have the TV cable thats currently in the car and I will be using a non electronic controlled quadrajet and I am going to reuse the stock brackets for the throttle/TV cable on the 350 I put in. All I should need now is a kit to conroll the lockup. Appreciate the help guys!
 

GoodOldsGuy

Member
Oct 20, 2020
41
8
Texas
Thanks for the info Goodoldsguy, the car is and early 85 before they made the switch to the olds 307/200-4r combo so it currently has a 700r4 in it which will be staying behind (for now) and I will be removing the current chevy 305 to upgrade to the 350. I do have a second 700r4 that I plan to rebuild and beef up a bit and install at a later date. My goal was to just have a nice cruiser with a bit more power, the 350 is baisically a stock build with an rv cam in it. I already have the TV cable thats currently in the car and I will be using a non electronic controlled quadrajet and I am going to reuse the stock brackets for the throttle/TV cable on the 350 I put in. All I should need now is a kit to conroll the lockup. Appreciate the help guys!
I did not know the 307 didn’t make it into Pontiac Wagons until 1986. I guess old dogs can learn new tricks after all. The worst part is, I actually owned a Parisienne sedan of that era, and it had a 305/700R4, so I should have made the connection.
 

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