85 k10 - Emissions delete questions

[76k5blazerr]

Picked up a one owner 85 k10 with my buddy today for him, 103k original miles. I assume it originally had a 305 but it has a crate 350 in it now with supposedly 10k miles on it. Opened the hood and could barely see the engine with the 100 miles of vacuum lines, so it has what looks to be 100% of the emissions crap still on it. Drove it home 2 hours, cruises fine at speed but doesn't idle very well and smells rich. I myself have had mostly 70s square bodies with no emissions equipment so I am a little unfamiliar with it. I just know that you don't need it, and it looks like chit, makes it harder to work on the engine and is just a general cluster####.

No emissions or visual/safety inspections for vehicles 35 years old or older here so that is no problem.

Basically what I was thinking of doing is totally ditching every single part of the emissions/AIR/smog system except maybe the charcoal can. My first thought was to install a non egr, regular SBC intake and a holley carb, and a regular HEI distributer to get rid of the ESC. Reason for wanting to change the carb is as you know, the 85 Qjet has all kinds of sensors and crap/electronic stuff to go with the emissions stuff, and I can tell its not all working right. Want to get rid of all the vacuum lines except a PCV and vacuum advance. Smog pump, AIR lines, everything needs to go.

However, after some of my reading before posting this I am seeing that there are some vacuum lines or wires for the 700r4 TC lockup that are somehow incorporated in the EGR system that need to stay, but there must be a way to keep the lockup working with an intake/carb swap right? This is my main question because I obviously don't want to screw up the trans.

A few other questions I have...

I know the factory Q-jet has some sort of solenoid that kicks the idle up to compensate for the AC compressor kicking on, is there a way to do that with a aftermarket carb such as a holley?

Can you make the cruise control work with an aftermarket carb?

I know that the 700r4 never came stock behind a totally non emissions engine like the 350s from the early 70s back, but people run them behind anything and everything now and they work, so there must be away to retain lockup and have it work right with an intake/carb swap??

Basically I think the best thing to do to make this a good running, reliable rig for him is to make the 350 like the one in my 74 k20, no BS, just a motor with a carb and an air cleaner... Is this do-able?

Sorry for the somewhat scatterbrained post, feel free to comment any insight you may have. Thanks fellas.

 

[dyeager535]

Does that carb have one or two electrical plugs at the front/top of the carb? If there is one on the front, drivers side then you'll have to replace the carb. Otherwise you'll have the option to leave the carb and intake pretty much alone.

Personally I like cruise control, would be another thing to consider keeping. It's essentially separate of all the emissions stuff, having it's own harness and hoses

 

[6872xtc]

Look for a switch on the firewall with one vacuum line and 2 wires. If equipped with it there is a switch for the TC lock. I don't remember the wire colors.
And I would ditch the electronic Q-jet for a regular one. But make sure that it has good throttle shaft bushings.

 

[76k5blazerr]

Does that carb have one or two electrical plugs at the front/top of the carb? If there is one on the front, drivers side then you'll have to replace the carb. Otherwise you'll have the option to leave the carb and intake pretty much alone.

Personally I like cruise control, would be another thing to consider keeping. It's essentially separate of all the emissions stuff, having it's own harness and hoses

I like cruise too. It doesn’t work right now but I am sure it’s just the turn signal stalk that is worn out. Are you saying that you can’t run cruise with an aftermarket carb? I guess buying a refurbished or rebuilt qjet would also be an option, one without all the crap on it.
@6872xtc
Are you saying just find the switch and make sure to leave it and it’s wires and vacuum hose alone and the lockup will be fine?

 

[6872xtc]

I like cruise too. It doesn’t work right now but I am sure it’s just the turn signal stalk that is worn out. Are you saying that you can’t run cruise with an aftermarket carb? I guess buying a refurbished or rebuilt qjet would also be an option, one without all the crap on it.
@6872xtc
Are you saying just find the switch and make sure to leave it and it’s wires and vacuum hose alone and the lockup will be fine?

I don't see any reason that you can't keep the cruise with any carburetor, you just need to have the extra stud on the throttle lever.
I not saying that the only thing needed to keep the lock-up working is the switch, but if it has it, the switch will help lead to what is needed.
It looks like these two examples.

 

[6872xtc]

And I know that it may be a little bit of a time delay, but I can highly recommend Sean Murphy Induction for a custom tuned and rebuilt Q-jet. My big block truck would not run properly after I installed a roller cam. After answering the questions about the truck and where I use it, his work made it run great! I only did some fine adjustments of the idle and choke.

 

[76k5blazerr]

Well when he went to crank the truck to bring it to my house this morning it wouldn’t start. No spark. Did the test light to the tach terminal on the coil and it wasn’t flashing but the coil does have power, so hoping it’s the module. Going to get a new one now.

 

[dyeager535]

Which carb do you have? CCC or not?

For the cost of a module, if it's not CCC, cant think of any reason you shouldnt just buy a complete distributor for $100 like you were planning on anyway.

 

[76k5blazerr]

Which carb do you have? CCC or not?

For the cost of a module, if it's not CCC, cant think of any reason you shouldnt just buy a complete distributor for $100 like you were planning on anyway.

Here’s a pic. Don’t see any electrical plugs so I guess it isn’t electronic like I original thought. You think the best option it to just grab a regular old hei distributor and bypass the ESC? We went to get a module but they did not have the 5 prong one that we needed. Only the 4 which I believe is for the older models. Frustrating.

 

[76k5blazerr]

I have read so much stuff in the last few days trying to familiarize myself with the differences in ignition systems from the 70s to 80s I had confused myself. But this article http://www.73-87.com/7387garage/drivetrain/escrepl.htm set me straight. So the way I understand it I can remove the ESC entirely and then install a regular hei dizzy, plug in the red wire and roll. So that’s the plan now.

 

[6872xtc]

I would keep that carb if it was me. It has the solenoid for the idle kick up with the A/C on, as well as electric choke. Plug off the ports that feed some of the other smog stuff and rebuild it. It could possibly have caps over the idle mixture screws, so those could get removed too.

 

[dyeager535]

Hard to tell, but is that a vacuum hose connected to nothing just forward of the internal fuel filter? (Where the fuel line enters the carb).

You might buy some time by just making sure there are no open vaccum lines, and those that aren't open appear to go to the right place. Lots of the plastic fittings and tees break over time, as well as hoses cracking or getting burnt.

Since it's only ESC, then replacing the distributor makes all the sense in the world. Plus, no spark could also be the pickup coil, and you'd have to pull the distributor for that anyway.

Might pull the number off that carb. Guessing both the distributor and carb are not for a 350, and getting the right distributor and tune for carb could make a significant difference.

 

[76k5blazerr]

Hard to tell, but is that a vacuum hose connected to nothing just forward of the internal fuel filter? (Where the fuel line enters the carb).

You might buy some time by just making sure there are no open vaccum lines, and those that aren't open appear to go to the right place. Lots of the plastic fittings and tees break over time, as well as hoses cracking or getting burnt.

Since it's only ESC, then replacing the distributor makes all the sense in the world. Plus, no spark could also be the pickup coil, and you'd have to pull the distributor for that anyway.

Might pull the number off that carb. Guessing both the distributor and carb are not for a 350, and getting the right distributor and tune for carb could make a significant difference.

It was originally a 305 truck, but has been replaced with a goodwrench 350. But obviously they swapped over all the accessories and carb etc from the 305. Yes it does have the solenoid for the AC. Most of the smog vacuum lines are cracked to hell. Carb is obviously leaking too. Maybe I will try just throwing a distributor in it and rebuilding the carb or getting a new qjet for it vs swapping it for a Holley. Distributor is first and I’ll see how it runs and go from there.

 

[dyeager535]

Its entirely likely that there is one or more vacuum leaks.

With the wrong carb tune (that is most likely an 800CFM variant, if originally on a 305) inoperative EGR alone will cause some part throttle cruise surging, and the EGR itself is probably wrong for a 350, so there's a bunch of things that could be working improperly.

Off the top of my head, you can plug essentially every vacuum line on that carb other than PCV, and that could give you an idea what you are working with.

Agreed, there is likely nothing worse than the 80's carbed emissions layout, I don't see much reason to spend a ton of time trying to diagnose potential issues with the emissions systems. Really the only reason to keep it is if someone in the future wanted to sell it to someone that had to go through a visual inspection.

Just dont yank stuff off willy nilly, so much of it is interrelated, you'd just want to make sure you weren't deactivating the TCC setup, EVAP, PCV, vac advance (if it even had that, cant recall with ESC) etc.

 

[kennyw]

If you are going to pull the carb and distributor anyway, it is only 13 more bolts to replace the intake.

You can get a correct, rebuilt qjet for about $310 https://swperformanceparts.com/A-TEAM1904R/

$100 brand new non-ESC distributor.

$50-200 for an aftermarket intake (good used or brand new).

$50-60 gasket set?

 

[76k5blazerr]

If you are going to pull the carb and distributor anyway, it is only 13 more bolts to replace the intake.

You can get a correct, rebuilt qjet for about $310 https://swperformanceparts.com/A-TEAM1904R/

$100 brand new non-ESC distributor.

$50-200 for an aftermarket intake (good used or brand new).

$50-60 gasket set?

Thanks for the link. That was my original plan, to replace carb, dizzy and intake. And @dyeager535 after we pulled off the huge stock air cleaner I immediately noticed several vacuum lines that were broken or severely dry rotted. I am going to find the torque converter and transmission related wiring/hoses and make sure to not disturb it and everything else sounds like fair game for the trash can. Thanks for all the info.

 

[6872xtc]

It was probably back in '08 when I got my carb built by Sean Murphy Induction, but it was $250 plus shipping back then. And he wanted to know everything about the truck, the elevation range that I am in, and what the truck was used for. I believe that I was into it for about $290 after shipping it both ways. He did offer to send one of his built and then mine was the core. I don't remember if that changed the price. I thought that it was cool that Sean himself called me to discuss it before he built it, which was exactly what his guy told me he would do.

@dyeager535 do you know why a 305 would have been an 800 cfm? That one would be desirable for some applications.

 

[kennyw]

Less than a year ago they were $289 from the same site. I had good luck with the one I bought.

 

[6872xtc]

Less than a year ago they were $289 from the same site. I had good luck with the one I bought.

View attachment 324518

That's good information and feedback. I personally would prefer one custom tuned for the same price though. When the guy asks the number of questions that he did, I feel that there must be a reason. But I haven't checked into SMI recently.

 

[dyeager535]

@dyeager535 do you know why a 305 would have been an 800 cfm? That one would be desirable for some applications.

I can only speculate, but GM did the same thing on the Olds 307 too...conveniently, after the 305 and 307 were both chosen to replace the respective divisions 350's. As the story goes, the 305 was supposed to mean the demise of the SBC 350. I find it odd GM made that miscalculation.

From testing I'd seen from folks like Vizard, the large CFM carbs help torque on the smaller motors. This flies in the face of "conventional" carb wisdom, but if you've been around long enough, you'll recall that the way that carb sizing was previously recommended, was even more basic than it is now.

I would speculate that since the difference is on the primary side, the additional CFM helped before the secondaries came into play. Probably let GM use the secondaries less often, which likely tended to improve economy, drive down emissions, and "feel" better to the driver since the tuning of the primaries is more precise.

Side note, the HO 305 in the Monte SS of the same vintages got the 750 variant. I don't know much about the b-bodies, but I bet the heavier cars with worse gearing probably got 800's. As the Old's 442 got the 800 as well, but had 3.42s vs. the SS' 3.73, I feel that also indicates GMs rationale.

AFAIK the 800 was the norm on 305 trucks. I didnt pull a ton of them off the trucks back in the day, but if I knew the truck was a 305, invariably I found an 800. I dont know if the bad gearing/800CFM combination was across the board on the truck 305. I cant recall if the 305 trucks could have been had with 3.73's. Would be interesting to know...OP might be able to answer that depending on the gears in this particular rig, if OEM.