A side project to get me away from the floorboard project which is dragging on forever!

Maybe I should be fielding this to Demon Dave but hes always busy testing tuning and rebuilding so in the event hes not out there in Moparts land. I know there are TQ owners out there...so I'll gladly accept suggestions from other TQ peeps...

TQ is a 9097S Application was 1976 Lean burn 400 with Auto.
Stock parts include Primary 4099 Sec 5413 Rod 2086 1.5inch pri bores so its an 850 CFM. Has the dual booster venturies.

Car 66 Coronet w 440HP TRW flat tops 906 heads and a 484/284 MP Cam - Headers and stock 4hole intake at the moment. Using an open 4bbl square to 4bbl spread adapter. I know a 4hole adapter would be better but its what I have...and I used it that way as a daily driver years ago.

I rebuilt the TQ all stock xcept new idle mixture needles I bought from Demon sizzler years ago that he said would provide more tunability...and they do seem to. Also bought a new set of o-rings from him since they left em out of my kit so its not leaking from the o-rings.

Sooo post rebuild....it idles but is SMELLLYYYY!!

Lean Burn carb? Nothing LEAN about it at idle and its
BURNing my eyes!!! On the plus side...I probably killed every mosquito for 2 blocks.

I tried turning the slow idle screw low as I could to cover the idle transfer slots as much as possible and still get a stable idle. Adjusted the timing a bit too. Sounds like its idling about 800 - 1000 in neutral and around 600-700 at idle but Im gonna use my shop tach tomorrow to verify. Mixture screws are out approx 1 3/4 turns. They are functioning and it tries to stall if theyre closed all the way. I set them by ear to max rpm. Idle is fairly smooth.

Question is...HOW do I lean this thing out? I was always taught to adjust mixture screws to max engine vacuum or rpm depending on what equipment is handy while achieving the smoothest idle...but its makin my eyes red and I smell like an exhaust pipe! Do the mixture screws adjust air or idle fuel? If they adjust air...turning them out leans it. If they adjust fuel...turning them out richens it. Seems like the way everything is routed end result is they adjust fuel flow at idle from the boosters?

The metering rod tree seems to be all the way down even tho I only have around 15in of vacuum at idle with this cam. I adjusted it prior to installing the carb but need to fine tune it now that my idle is set. Do metering rods and main jets affect idling at all? Im askin bcus if metering rods don't affect idle fuel I'm yankin em out for now till I get to fine tuning it for performance bcus it repsonds much quicker without them. I used to drive it that way on the street but it wasnt great for fuel mileage. It stunk at idle back then too. The rods are still in place right now.

BTW I already drilled 1/8 holes in the primary plates years ago bcus it used to sit on a high rise intake but I mig'd them closed 2 days ago bcus after I fired it up it wouldnt idle down. Turns out I had a bad base gasket which I replaced with a new one and the accelerator cable was pulling on the throttle a bit so those holes may or may not have needed to be filled. I'd rather not re-drill them If I dont have to.

Thanks in advance for any suggestions
Dave

With that cam it probably isn't pulling the tree/metering rods down fully at idle, might need a different spring... Also are you sure the O rings in the main wells are in place and in good shape...

WOW! Super svc response! LOL!

I did check...the tree is down fully and I adjusted it per instructions I found online. I should probably fine tune it a hair now that I have a slightly different slow idle adjustment than the base tune I gave it b4 install just adjusting for idle transfer slot size to be a small square.

Do main metering jets/rods affect idle? Or just mixture screws?
Will yanking my rods out make it even richer at idle? I havent yet but nice to know.

Orings are brand new. Bought them from Demon Dave too.
Got a few sets but they all looked the same to me so I
threw a pair in.

If the tree rises the mixture will go fat.. It's intended as cruise enrichment but it will pull fuel at idle... BTDT And yes tweaking the screw in the center of the tree can also effect idle mixture but mostly it is the key to tuning the cruise A/F mixture..

Ok...so if the tree affects idle too...then you're saying the main jets do flow at idle and yankin the metering rods out would theoretically make it richer at idle too.

If true....then... maybe I need a rod profile thats leaner at idle and richer top end. Im not sure WHY a LEAN burn carb would idle so richly on a high perf engine when it was designed for a low perf engine and should've had lean metering rods even at idle.

What about idle air bleeds? Any idea there? Make em larger? smaller? Leave em and try a single 1/16 hole in one throttle plate to see what happens? Put a hole in a vacuum plug for a controlled vacuum leak to lean it? LOL!! I'll try anything

The metering rods have no effect on the idle circuit. If the metering rod tree was bouncing, it only means that the vacuum of the engine is
erratic or lower than it should be. Primary jets also have no effect on the idle circuit.

If you used a QuadraJet base gasket, it will not worn on an 850 cfm T.Q. because it causes disturbance at the primary opening in the gasket
(for 1-3/8" primary bore vs 1-1/2 bore for the T.Q.)

Also I believe you may have the main idle speed too high thus over exposing the idle transfer slots to get the engine to idle high enough.

You should advance the initial timing, then back down the idle speed, David.