Stock 85 Cut Sup Bro Exhaust and parts recommendations

Oct 14, 2008
8,325
113
Melville,Saskatchewan
Just change the choke pull off and make sure any questionable vacuum lines are replaced. The tension for the secondary door is set too light. I find this on every Qjet I come upon is that way. It just requires an Allen key and a small standard screw driver and will eliminate a secondary bog. Don't go with a Edelbrock carb, they usually run terribly on an Olds and will need major retuning on a 307. Headers can be a PIA to install. But headers and duals on an Olds add 30 HP, it has been dyno proven on Olds 350's and 455's. On the 350 and 455, the better Thornton manifolds were used on that dyno run, showing full length even a bigger gain over regular SBO manifolds. Those swirl port manifolds are particularly bad for flow, along with the factory crossover pipe and single exhaust. An O2 sensor bung will need added on any aftermarket system, I would also do the heated O2 conversion, especially with headers. You could go with Thornton manifolds and custom dual exhaust. A 2.25" system would be plenty big enough. You will need a dual hump crossmember with full length headers. A custom bent 2.5" dual system can fit all under the passenger side hump, I had one done. Thornton and Sanderson also have shorty headers. Hedman has a shorty that is more of a mid length, it makes exhaust routing more difficult, the collectors point straight down. The Hedman are the only cheaper full length headers worth buying. What transmission does it have? The TH2004R overdrive will allow a gear swap that will make your car feel much faster and highway rpm will still be acceptable. Good luck.
 
Last edited:

Cabal

Not-quite-so-new-guy
Thread starter
Apr 12, 2022
6
3
Southern Kentucky
I see something else...

Your secondary flaps are hanging open. What up with that? When that happens, your secondary rods are pulled up and potential for fuel to be pulled into the secondary system, which really will fugg up your fuel curve. The ECM does not even see the secondary system on the carb. Additionally, you have a hose for a fuel line. It would be best if you could get a steel line from the fuel pump to the carb. Just throwing that out there.

If you need a rebuilt carb, have YOUR carb rebuilt.

It appears you may have a loose or broken spring on the secondary flap adjustment.
The secondary's have never worked since I've owned the car. The secondary's literally flap around with no tension and, when running, rest closed. This picture was taken a while ago before the crack fully formed in the diaphragm. I keep them closed but took this picture with them open to show someone if they could spot the issue. You are right and I was lazy whenever I replaced it with a rubber hose.

I really want to have my carb rebuilt. I like the idea of keeping this car original, but, I've asked nearly every mechanic, speed shop and old Joe down the street and either they don't want to or don't know how.

I'll definitely check the spring when I get home today.

I'm about to dox myself a bit but I live near Bowling Green, Kentucky. Holly Carbs headquarters and plant is there and so is Quick Fuel. I know that you can get cars worked on there but I've hesitated due to money in the past. Maybe it's time I reach out.
 

Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,415
113
Galaxy far far away
The secondary's have never worked since I've owned the car. The secondary's literally flap around with no tension and, when running, rest closed. This picture was taken a while ago before the crack fully formed in the diaphragm. I keep them closed but took this picture with them open to show someone if they could spot the issue. You are right and I was lazy whenever I replaced it with a rubber hose.

I really want to have my carb rebuilt. I like the idea of keeping this car original, but, I've asked nearly every mechanic, speed shop and old Joe down the street and either they don't want to or don't know how.

I'll definitely check the spring when I get home today.

I'm about to dox myself a bit but I live near Bowling Green, Kentucky. Holly Carbs headquarters and plant is there and so is Quick Fuel. I know that you can get cars worked on there but I've hesitated due to money in the past. Maybe it's time I reach out.

Most modern professional mechanics are not taught how to work on carburetors anymore, they only know OBD2. Many don't like to work on older cars at all. You will likely need to send your carb to a Qjet specialist like Cliffs Performance or Sean Murphy Induction. Its not a job you can have done locally in most areas anymore.

Do not exchange your Qjet for a already remanufacured one. Remanufacturing and rebuilding are two very different processes, you only want rebuilding. Even with the best rebuilders, you must perform the final tuning on the carb while your engine is running.
 
Last edited:
  • Like
Reactions: 1 users

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
7,028
113
You may also consider


The guy can do you right with an e qjet. For the price of one of those crappy Edelbrocks, he can fix yours to run like new again.

Last time I got a quote from him it was like $400 for a complete show restoration. Basic rebuild was less, obviously. But it should work. Haven't heard a bunch of problems from his carbs.

E-Quadrajets aren't that difficult if you have the service procedures. They're tedious, yes, as you need to adjust them to within specs and the special little tools that make it easier to do and not everyone has them, but they're not THAT hard. Parts are still somewhat available from various sources, so it can be done.
 
  • Agree
  • Like
Reactions: 2 users
Oct 14, 2008
8,325
113
Melville,Saskatchewan
The Quickfuel 600 cfm will need jetted down a bunch to be anywhere right. Honestly the 625 cfm Street Demon is a better choice on a 307 but will also be rich out of the box. Remember you also must change the distributor to a vacuum advance model. You can make the secondary door open fully on your Qjey, they restricted the factory, adjust and add richer secondary rods, all pretty easy. Ken at Everyday Performance is probably your best bet for getting your electronic Qjet rebuilt. Mention you are adding headers and duals and better performance, he can do those tweaks I mentioned. He did a good job on my regular Qjet. You will gain way more with the headers and dual exhaust than swapping your carb, especially out of box.
 
  • Like
Reactions: 2 users

Cabal

Not-quite-so-new-guy
Thread starter
Apr 12, 2022
6
3
Southern Kentucky
If you need a rebuilt carb, have YOUR carb rebuilt.

It appears you may have a loose or broken spring on the secondary flap adjustment.
I think I've found a company to rebuild it and that's the track I'm going to take after talking to you and others on here. It makes way more sense seeing that GM engineers spent time and money pairing the two.

I did as you suggested and the spring is 100% broken or bent. You can hear the classic creaking noise when I was turning the screw. However, with the help of a friend, we were able to manually activate the secondary's a few times and HOLY CRAP! I've had people explain to me what it sounds like and heard videos of a Qjet opening up but it didn't prepare me for it. I literally jumped back the first time it happened and it sounded like a totally different car.

Now it's time to figure out which company I'm going with for the rebuild and figure out which headers to go with and get this ball rolling.
 
  • Like
Reactions: 1 users
Oct 14, 2008
8,325
113
Melville,Saskatchewan
Make sure they are a small carb rebuilder like Everyday Performance NOT a remanufacturer. If they have remanufactured anywhere on their site, run away!
 
  • Like
Reactions: 1 users

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
7,028
113
Looking at the picture of your engine some more...there's a few other things that concern me.

I circled them for ease of locating them...

Ok, the first one I didn't circle, but right on top of the carb in front of the primary choke plate, you'll see the idle air bleed valve adjustment screw. DO NOT MESS WITH THIS unless you know what you're doing. It's supposed to be set within a certain parameter in a certain way and be left alone. It's really a set it once and forget it deal. Not a constant tweak point. The factory caps this with a little plate with micro rivets to keep people from messing with it. This carb has been messed with before.

Red - WTF? This looks like some sort of electrical plug, but to where? My mind is going on me, but that isn't the O2 sensor wire is it?? Or the plug for the A.I.R. diverter valve that doesn't seem to be there? Now I'm guessing the A.I.R. system has been removed?

Green and purple- the green shows the "VD" stamp on the ORIGINAL factory PCV hose. Purple circle shows what appears to be a 12/10/84 manufacture date. Hard for me to see because I'm old as dirt, but that's what it looks like from here.

Purple arrow- note the age/heat cracks. This is more what I was talking about as far as potential air leaks. Hose may LOOK ok, but look closer and note the cracking.

This was what I was talking about checking the vacuum hoses and rubber bits for age/wear/damage/cracking to ensure you're eliminating as many vacuum leaks as possible.

Ok, moving on...

Gold- appears it's not even hooked up. If you have gages or not, this sensor either grounds and shows the dash HOT light, or if you do have gages, has the temp gage AND "HOT" light sensor all in one. Either way, the plug doesn't seem to be there. It might be as the cruise servo is in the way, but I'm not 100% sure. Seems like the wires are nearby.

The next two are not issues I see, but since I'm here, I'll just point them out so you know what they are.

Light purple- This is the green grounding plug. This is important. When doing dwell meter work while adjusting stuff, you can use this for your dwell meter hookup and be good to go. Don't tape this off or cut it out from the system if keeping the ECM. It's supposed to hang loose and just be there but also insulated from touching metal. I've seen the green plastic busted on these before with exposed terminal. Bad idea.

Light blue- This is your ECM sensor for coolant. It basically tells the ECM what your coolant temperature is so it knows to make an adjustment or not. Your ECM needs this, otherwise you could stay in open loop forever and never get your fuel controlled. Your engine already has had the upgrade because the big round clip is gone that would be found only on the originals. There was a service bulletin concerning this way way back, a long time ago, to swap to the new sensor and plug. I know, they did it to mine and I didn't want or authorize it. I also see from the wider metal clip on the cruise servo bail you've had the recall done on the cruise unit as well. That was a big deal over nothing, really. JMO.

85 VIN Y engine compartment marked up.jpg
 
  • Wow
  • Like
Reactions: 1 users

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact Admin@GBodyForum.com for info on becoming a sponsor