Close the plug gaps to 45 thou using the right tool. Apply some fuel prep, and run its azz off.
The reduction of PCV to the base of the carb will help idle and off idle. It needs to be a balanced system.
Then, gotta say it, beg, steel or borrow a color tune, and set the mixtures, or just check what they are.
Before I started, with Frankenstang in fact, I got the Black Hawk Engineering General Jet & Rod Tables pdf, and ran every known rod and jet combo verses each in line six engine family, and worked out the Jet Area minus rod area times 100,000 from the charts on.
http://www.blackhawkengr.com/General%20 ... Tables.pdf
Back in 2015, I had most of the info, but the AMC stuff was the key, because it showed me how a 300 carb behaved with less capacity since all the Ford data is missing from IMCO/Thermactor, right up to OBD1.
I calculated the 98 thou jet verses the stock 75-2079 lean metering rod which would have actually been an early 300 with 107 thou jet, so the 7115S carb you have was set up for what became a 120 hp net engine.
Your peak air fuel ratio at wide open throttle is wound back 24% , and at cruise, 29.5%, since your exhaust headered, 5 speed 200 engine is 50% smaller, and, probably, an honest 93 hp at the flywheel.
I got a comparitive jet/metering rod from 199 and 232 AMC's, and your 75-2079 metering rod with 98 jet is leaner, but they also showed the same sensitivity to 4cfm uniform flow PCV valves, and required a pealed back 1.5 cfm wide open throttle PCV rating. Block off the PCV, idle always improves. 75-2147, 101 and 75-1990, 101 jet, they work well. Those engines have a very lean cruise, a very rich idle, and a not very rich wide open throttle.
The rules are, if you can prove rich or lean by WOT plug readings, and idle by color tune, and mid range by loaded uphill 2nd gear 30-50 mph acceleration, you can then tailer the fuel curve.
So at the very most, you might want to look at either a 101 main jet later on if your mixtures with the PCV really are lean. Which I very much doubt.
Mike has a 75-1986, which, with your stock 98, richens the idle, and leans off the cruise, and keeps Wide Open throttle just the performance side of stoich.
I'm banking that it would be ideal.
But your baseline is having 100% ignition, a reliable air fuel determination, and then, having just a few tricks to trimming air fuel. Like a couple of lights on the 1/4 mile Christmass tree, optimisation is the key.
I just found your carb.
http://www.ebay.com/itm/281348982040?it ... rmvSB=true
300, right down the line.
Be cool. I'm away for a while. I wouldn't drill the top for acess to the screw, even though we know its got 10 revoltions, and a thread pitch, and you could make it an "Adjusta-Jet". I'd focus instead on air fuel calculation at four static points, WOT, cruise, and idle, and making sure transition at 30 to 50 mph in 2nd is good.
You can do a huge amount will just a narrow band O2 sensor if you have shut off wide open throttle plug readings.
The true magic is that this is what Americans do better than anyone...make things work.
Just been reading about the old Carter ACF company base in St Loius.
https://www.hemmings.com/blog/2015/08/2 ... nt-page-1/
You know, the 1953 YF carb, and the 1946 YS Jeep carb that gave it birth, lasted untill 1990 in some Jeep models. Its nothing to have an engine that lasts 37 years, but a carb, well, thats special.
I like the engineering and simplicity. I don't think this little jug is going to bite you, its a special little device.
