Need help w/ a few things! 🙏 TBI conversion to Carb.

[MonteLS_84]

Wageslave CopperNick

So, after nearly 3 months of being in the shop, my car is just about ready. The guy ran into a problem though, and I'm looking for second opinions.

Long story short, swapped out stock components for performer rpm intake, xe268h cam, eddy 650 carb., MSD hei dist., and 3.73 posi.

The th350c trans was rebuilt...for lock automatic lockup (I requested not to have a switch). So, I get a phone call today that the distributor I got won't work. He claims the trans. is still using the ECM to lock up, and therefore I either need to use the OEM distributor, or one that will work. The solution we came to was that he would switch caps out, and retain the rest from OEM.

I'm worried about the carburetor and distributor being controlled by ECM if that is hooked up, or do I assume he knows what he's doing, and it won't? (I will ask tomorrow but...)

Does this sound kosher? Also, I tried Google, and couldn't quite come up with an aftermarket distributor that has the same plug in required for ECM (for trans.). 🤔

Any help would be greatly appreciated.

Here's a video of the current progress. Not great quality but..

IMG950488.3gp

drive.google.com

 

[64nailhead]

Install a manual lockup kit that eliminates the computer or a dash mounted switch. Both will work.

I haven’t read the entire thread. So perhaps my advice is a little off base. But eliminating any control of the ecu over your engine or trans will make things easier.

 

[ELCAM]

Pickups didn't have computers till the late 1980s. Here is how they worked.

 

[CopperNick]

Just to clear up something up here, the term "Wageslave" is not part of my forum name. That said, when you have to keep working because the government pension dole is so thin it won't even pay for your overhead costs then you do tend to form some kind of symbiotic relationship with work, simply to be able to afford to exist.

Moving On.

I personally do not think the presence of the lockup is all that critical. If you are still running that OEM ECM then you still need to use the versions of the carb and the distributor that match it. The plug in to the transmission shows four pins but the male end possesses only one. My last 350 was the E version and it worked happily for over 30 years without never did getting its connection actuated. All that connection does is to actuate the lockup option in the converter. No juice, no lockup, no problem. The 350 doesn't depend on e-input to tell it when to shift. That is controlled by the modulator valve which in turn uses engine vacuum to come and go.

Summarily, Having the ECM still resident and operative means using the carb and distributor that match it.

Not having the lockup electrical connection plugged into the transmission Only means that the box won't lockup in third.

The ECM aka OBDI mostly and typically only controlled ignition advance, based on input from the carb and various sensors.

Likely to be exceptions here but typically, the TH350 3 speed transmission was governed based on vacuum. The cable mechanism is a mechanical link that physically forces the box to downshift to compensate for increased acceleration such as that which occurs during passing another vehicle.

I expect and welcome comments and additions to this thread/my response as I know there is probably some niggling detail that got missed.



Nick

 

[MonteLS_84]

Just to clear up something up here, the term "Wageslave" is not part of my forum name. That said, when you have to keep working because the government pension dole is so thin it won't even pay for your overhead costs then you do tend to form some kind of symbiotic relationship with work, simply to be able to afford to exist.

Moving On.

I personally do not think the presence of the lockup is all that critical. If you are still running that OEM ECM then you still need to use the versions of the carb and the distributor that match it. The plug in to the transmission shows four pins but the male end possesses only one. My last 350 was the E version and it worked happily for over 30 years without never did getting its connection actuated. All that connection does is to actuate the lockup option in the converter. No juice, no lockup, no problem. The 350 doesn't depend on e-input to tell it when to shift. That is controlled by the modulator valve which in turn uses engine vacuum to come and go.

Summarily, Having the ECM still resident and operative means using the carb and distributor that match it.

Not having the lockup electrical connection plugged into the transmission Only means that the box won't lockup in third.

The ECM aka OBDI mostly and typically only controlled ignition advance, based on input from the carb and various sensors.

Likely to be exceptions here but typically, the TH350 3 speed transmission was governed based on vacuum. The cable mechanism is a mechanical link that physically forces the box to downshift to compensate for increased acceleration such as that which occurs during passing another vehicle.

I expect and welcome comments and additions to this thread/my response as I know there is probably some niggling detail that got missed.



Nick

Thanks for the valuable reply! By the way, WAGESLAVE was someone else that I tagged who seemed to have extensive knowledge on the th350c as well. 🙂

Turns out I got a phone call this morning. My mechanic informed me that after much troubleshooting, his supplier actually sent him the wrong (non lock-up) torque converter. He then added that my new MSD hei distributor should work just fine.

That said, it makes me nervous when things like this happens because I can't help but question whether someone really knows what they're doing, or not. But...I also understand that not everyone is going to be 100% familiar with how this year of Monte Carlo operates, not to mention how a th350c operates (most people I ask never knew they exist).

So, fingers crossed 🤞- the proper 2300 stall lock-up converter should be there in the morning...and I can finally pick my car up.

I will definitely send an update video.

Lastly, I have to mention that retaining the lock-up function was my plan all along. So, simply disconnecting it, etc. isn't an option. I paid for a Bowler kit for lock-up, and trans. is already rebuilt. 🙂

 

[64nailhead]

The issue you're having is not uncommon in todays repair shop world. Most of the guys that know how to do what you've requested are not young - repeat - most.

Check codes, change a part, hope it fixes it, if it doesn't tell you to take it to the dealer, and BTW - here's your bill. Very little diag is done nowadays as compared to when you had to understand mechanical failures and mechanical systems. I'm not generalizing about all mechanics, but just many. I watched a young guy swap in a 200-4r into an El Camino at a 'shop' and break the pump while sucking the trans onto the motor. When I mentioned that the car will never move, he wanted to know how I knew that. The issue was he asked me two days later when the car didn't move.

 

[64nailhead]

Turns out I got a phone call this morning. My mechanic informed me that after much troubleshooting, his supplier actually sent him the wrong (non lock-up) torque converter. He then added that my new MSD hei distributor should work just fine.

That said, it makes me nervous when things like this happens because I can't help but question whether someone really knows what they're doing, or not. But...I also understand that not everyone is going to be 100% familiar with how this year of Monte Carlo operates, not to mention how a th350c operates (most people I ask never knew they exist).

So, fingers crossed 🤞- the proper 2300 stall lock-up converter should be there in the morning...and I can finally pick my car up.

I will definitely send an update video.

Lastly, I have to mention that retaining the lock-up function was my plan all along. So, simply disconnecting it, etc. isn't an option. I paid for a Bowler kit for lock-up, and trans. is already rebuilt. 🙂

Ya know, our cars are a hobby. They are great fun to drive and take pride in. But there is an opportunity for learning. And that is one of the best parts of this hobby AFAIC. Perhaps I'm a pessimistic person that will die unhappy, but I only put trust into those that have earned it when it comes to my hobby (cars). You could do yourself a tremendous favor and learn as much as you can as you go. And understand that there is always more to learn. I'm a knowledgeable person about motors, car electronics, but I am NO expert and I'm doing my damndest to learn more every day - that's the fun of cars IMO.

I hope your car upgrades turn out the way you want, but if they don't then don't get disappointed. But rather 'dig in' to learn what's up and how to resolve issues and make the car work the way you want.

I find more enjoyment in learning than bragging lol. Good luck - Jim

 

[MonteLS_84]

Ya know, our cars are a hobby. They are great fun to drive and take pride in. But there is an opportunity for learning. And that is one of the best parts of this hobby AFAIC. Perhaps I'm a pessimistic person that will die unhappy, but I only put trust into those that have earned it when it comes to my hobby (cars). You could do yourself a tremendous favor and learn as much as you can as you go. And understand that there is always more to learn. I'm a knowledgeable person about motors, car electronics, but I am NO expert and I'm doing my damndest to learn more every day - that's the fun of cars IMO.

I hope your car upgrades turn out the way you want, but if they don't then don't get disappointed. But rather 'dig in' to learn what's up and how to resolve issues and make the car work the way you want.

I find more enjoyment in learning than bragging lol. Good luck - Jim

I totally agree. My main bottleneck is that I don't have a garage, and I live in the north midwest...maybe that's an excuse but I tend to limit myself to smaller jobs in the driveway. Pulling the engine and doing all the work that I've outsourced wasn't really practical.

I've been salivating at the thought of having a garage built...but...

As far as having someone else do the work, that wasn't my ideal choice...just necessity. Actually, I couldn't find anyone local that even wanted to take the job on. 😒 The guy doing my trans. just happens to also be a "retired" drag racer / engine builder, and thankfully he took up the challenge. I'm just hoping all comes out to my minimal expectations. 🤞

 

[Wageslave]

Congratulations on getting this close to done. While I tend to want the lock-up to be working, just for the 2-300 RPM drop and the feel of a virtual 4th gear, it is totally optional and will not have any effect on the life of the transmission. I actually left mine disconnected, since 2.41s need so much force to keep moving. With your 3.73s, I think it would be a good idea to have it working if possible, especially if you are doing extended highway driving or interstate driving. Manual lock-up kits are available through Jegs or Summit, and are not terrible to install.

They can also be wired up to be locked up any time you are in 3rd gear if a normally open pressure switch is added to a port on the valve body. Then you just add Ignition ON power to the lock up wires and you are good to go. The trans pan has to be dropped to do it, but it never has to be thought of again after it is done. I did this to an old square body truck I had many moons ago and it worked as good as the factory lock up setup did. It just feels like a slightly steeper drop in RPM's between second and third.

Hope this helps.

 

[ttype]

Without having finished reading the whole thread through... is that air cleaner pushing on sparkug boots for cylinder #'s 1 and 8?