Stock 85 Cut Sup Bro Exhaust and parts recommendations

Cabal

Not-quite-so-new-guy
Apr 12, 2022
6
3
Southern Kentucky
Hey everyone,

I'm brand new to this forum. I've used posts and FAQ's to see answers to my questions over the past few years but I've finally made the dive to create an account and to ask a few things.
I have a bone stock 1985 Cutlass supreme with a 307 that's never had any major work done to it. As in the only things done are: K&N air cleaner (Stock can), crude smog by-pass, general maintenance (pulgs, coil, filters, ect.).
Engine and trans have never been out of the car, it's always been in the family and, thanks to my grandmother, I have receipts and work orders for everything that's ever been done to the car.
I've finally landed a job that allows me to start working on it and I've recently purchased an A-body Cutlass so I have a new daily.

I'm currently looking for bolt- on headers (preferably long tube and with an O2 cutout), a decent carb replacement for the quadrajet that's on it or repair if it's feasible (nothing crazy, decent MPG/HP ratio), body panels/parts and about a million other things.
The current goal is to make it reliable, sound nice and be fast enough to get out of its own way and to drive it with the 307 until it fails.

Thank you for any help or suggestions
______________________________________

Some back story if you want it- Grandma ordered this car through and Old's dealer in late '84 as a Christmas present to herself. It was shipped from the factory to her and she accepted delivery in June of '85. The delivery driver scratched the door and left a 3 1/2" mark on the driver side and I have a receipt of when it happened, how it happened and for the repair done at the dealer later that week. I have pictures of my parents holding me a few days after I was born in front of the car. I have others where I was 6 eating a moonpie in the passenger seat and sitting on the hood when I was 4. The first doughnuts I ever experienced was in the passenger seat of this car after it had snowed when I was 6 and my dad begged me not to tell my mom or grandma that he had done them. I knew I wanted it to be my first car when I was 8. It's been my dream car ever since then. It had sat in a field for 7 years and a garage for 5 years after that. My grandma gave it to me when I was almost 19 after 4 years of constant pestering. It took me about 2 months of: going to work, getting off, driving 20 minutes outside of town, working on it for 4-6 hours then driving back and going to bed to finally get it running. It was my daily driver for nearly 10 years. It has never left me stranded or let me down. The secondary's have never worked on it. I didn't realize that it had cruise control for 4 years because the writing had worn off the stalk. Over the years I've been offered anywhere from 6 to 10K for the car. I will never, ever get rid of it. If I don't have kids by the time I die, I'll be buried in this car. My grandma named the car Bessy and it's stuck.
 
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doood

Amateur Mechanic
Sep 24, 2020
264
93
I was under the assumption that the factory quadrajet with the computer the car has is the best fit configuration for that motor. I understand you probably have the later heads which don't flow as well as the '81 vintage heads. Not sure what you've deactivated with the "crude smog by-pass", but I figure you kept the O2 sensors in the loop.
 
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Cabal

Not-quite-so-new-guy
Thread starter
Apr 12, 2022
6
3
Southern Kentucky
I was under the assumption that the factory quadrajet with the computer the car has is the best fit configuration for that car. I understand you probably have the later heads which don't flow as well as the '81 vintage heads.
I was too. The people I've talked to who know what they are talking about say "They're great carbs, when they work." I have no knowledge or repairing whatever is wrong with it and can't find anyone locally either. Yea, the stock headers look like milkshake straws. I've recently had issues on cold start-up, the car starts bogging and trying to die while it's spewing out black smoke. It clears up after it shifts to second gear or after 45 seconds of me keeping the idle up. I think the electronic choke is messed up? I honestly have no idea though.

-BTW I'm jealous of your cars body lines and your AR TT rims.
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
7,028
113
You should have a hot air choke if completely stock. Sounds like the diaphragm in your primary choke pulloff (pass side front of carb) is leaking/busted. If you take a vacuum tester and try to pull a vacuum on it, you'll be able to tell right away. My suspicion is that it's messed up and isn't pulling the choke open partially on cold start. Once it warms a bit and the choke starts to open the choke flap a bit then the pull off has no real effect and the car clears up the rich condition. Otherwise it spews black gas-rich smoke until it dies or you give it some gas.

Pull the air cleaner off when it's dead cold, have someone pump it to set the choke and high idle, start the car and see if the choke flap opens about 1/8" or so. If it doesn't, the primary choke pull off is fugged.

The A5 intake and 7A heads SUCK for performance, so don't waste time putting money into headers. It is a lot of work for minimal gain.

The age of the car dictates you should, at a minimum, go over every vacuum hose on the engine to ensure you minimize/eliminate any and all vacuum leaks.

Unfortunately, the only plus about your engine is that it's a roller cam engine. But it isn't the best bang for the buck as far as hopping it up for more power. It just wasn't all that and a bag of chips. It was more for smoothness and reliability when taken care of. Not bashing it, because a well-tuned 307 is perfectly fine for the application.
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
7,028
113
Not exactly your carb, but the choke pull off is located in the same spot on yours as on this one. For illustrative purposes only. Standard Parts CPA177 (or equivalent) is what you want if you need a new choke pull off. Around 20 bucks.


17085594lfq.jpg
 

Cabal

Not-quite-so-new-guy
Thread starter
Apr 12, 2022
6
3
Southern Kentucky
You should have a hot air choke if completely stock. Sounds like the diaphragm in your primary choke pulloff (pass side front of carb) is leaking/busted. If you take a vacuum tester and try to pull a vacuum on it, you'll be able to tell right away. My suspicion is that it's messed up and isn't pulling the choke open partially on cold start. Once it warms a bit and the choke starts to open the choke flap a bit then the pull off has no real effect and the car clears up the rich condition. Otherwise it spews black gas-rich smoke until it dies or you give it some gas.

Pull the air cleaner off when it's dead cold, have someone pump it to set the choke and high idle, start the car and see if the choke flap opens about 1/8" or so. If it doesn't, the primary choke pull off is fugged.

The A5 intake and 7A heads SUCK for performance, so don't waste time putting money into headers. It is a lot of work for minimal gain.

The age of the car dictates you should, at a minimum, go over every vacuum hose on the engine to ensure you minimize/eliminate any and all vacuum leaks.

Unfortunately, the only plus about your engine is that it's a roller cam engine. But it isn't the best bang for the buck as far as hopping it up for more power. It just wasn't all that and a bag of chips. It was more for smoothness and reliability when taken care of. Not bashing it, because a well-tuned 307 is perfectly fine for the application.
Thank you! Whenever I have time, I'll check out the choke situation.

The headers and exhaust are more for sound than anything. From the factory these things had like 140HP? I know this car will never be fast without doing a lot to it. Honestly, I just want dual exhaust that sounds nice and looks good.
To change out the headers, is it not a simple "remove old, replace new" situation?

At this point, I've replaced almost all of the vacuum hoses in the engine bay. All the T fittings and adapters and check for leaks about every 3 months using break fluid or carb cleaner.

Even if I end up doing full drivetrain swap, I'd still want it to be a highway cruiser. 40-80 pulls, wouldn't care about 0-60, top end or even handling for the most part.
My favorite moments in the car are going over whoops in the road with a friend whose never been in it and it floating around and cruising between 55 and 65 on highways and I want to keep it that way. The carb has never had working secondary's and I was a dumb kid once and mangled the exhaust. I'm just looking to spiff it up a bit and enjoy it.
 
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oldsmobile joe

Royal Smart Person
Nov 12, 2015
2,044
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The headers and exhaust are more for sound than anything. From the factory these things had like 140HP? I know this car will never be fast without doing a lot to it.
What do you mean. Loud exhaust is good for at least 50 horse.
 
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Cabal

Not-quite-so-new-guy
Thread starter
Apr 12, 2022
6
3
Southern Kentucky
You should have a hot air choke if completely stock. Sounds like the diaphragm in your primary choke pulloff (pass side front of carb) is leaking/busted. If you take a vacuum tester and try to pull a vacuum on it, you'll be able to tell right away. My suspicion is that it's messed up and isn't pulling the choke open partially on cold start.
You were 100% correct. There's a hair line crack in the choke diaphragm and I was able to have my dad start it while I held my finger over it and had no issue. Turned it off, removed finger, started again, back to sputtering and black smoke until it warmed up. I'll hold off on ordering anything for it for now until I figure out if I'm going to replace or repair the carb.
20210608_144623.jpg
 
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Clone TIE Pilot

Comic Book Super Hero
Aug 14, 2011
3,415
113
Galaxy far far away
You could send the carb to a quality rebuilder like Cliff Ruggles or Sean Murphy. Also might want to pick up Doug Roe's Qjet book.
 

69hurstolds

Geezer
Supporting Member
Jan 2, 2006
7,028
113
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 goes with your car and you know it should work. I wouldn't go get an edelbrock if it were me. You'll probably cause more issues than fixing. You will either need to disable the CCC system completely to use an Edelbrock carb, or get another CCC carb. Otherwise your car will run like sh*t no matter what you do. Messing around with the systems on your car requires knowledge of said systems. Meandering around piddling with this and piddling with that without knowing exactly how the car should react when you're done can get your car way out of whack, throwing codes, and causing issues.

It appears you may have a loose or broken spring on the secondary flap adjustment. The picture below can help you with adjusting the spring tension provided it's just loose. Just make sure to hold the spring fulcrum pin with a small flat blade screwdriver when loosening the set screw or it will unwind instantly. If the spring is broken, you'll need to replace it. Normally, you would want to tighten the spring until the air flaps JUST close, then 1/2 turn tighter, then tighten the set screw. Adjust slightly as necessary after a test drive. The goal is smooth transition to the secondaries without hesitation/bog.

Quadrajet secondary air flap adjustment.png


2018-02-09-09-45-20-020788.jpg
 

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