i figured i'd share some of my success with carb tuning with you fellas since you've always been willing to share advice with me. by no means is this the perfect tune, it has worked well for me, but i'd suggest reading this book:
http://books.google.com/books/about/How ... ZrJgUAlRYC

to get a basic knowledge of what's going on inside, and using this as a baseline.

The setup

-holley 2300 - list 4412 - 500cfm - 50cc accelerator pump with a brown cam and a 6.5 powervalve
-Slant six with a 2bbl manifold, 2 1/4 exhaust, engine is over .060 with the stock head (tube style) and i'm running a colder plug (autolite 63)

http://m.summitracing.com/parts/hrs-752002-10 this is the cam I have in it.

Initial findings

This carb came with #73 jets and a 50cc accelerator pump, which is overkill for this engine, especially with the 500cfm rating. essentially, its wayyyy to big of a carb for the slant six. But i like to tinker, and i wondered what i could do to get it to at least perform well without spending a ton of money or mods.

Plan of attack

i removed the #73 jets and replaced it with #67 to start (i purchased http://www.jegs.com/i/JEGS+Performance+ ... 3/10002/-1 from jegs and a rebuild kit with the nonstick blue gaskets.)
after the rebuild i set the float level as per the holley video instructions (shake the car and it comes out of the sight plug) and ran the car.
wayyy still too rich. i went down in jet increments from #67 to #64 and finally settled on #61. the car ran better, but still not right. i decided to fight with the ignition first and get that to match the carb. i put in an HEI setup and got a low resistance e-core coil from accel with the highest winding ratio.

i replaced the heavy springs in the distributor with the lightest ones i could find so i could get advance quick and the vacuum advance is a VC-208 with the following specs - VC-208: 6" / 10° - 12° @ 9" - 11" (thanks dan)
initial timing was set at 10btdc.

i lowered the float level slightly and that helped. we were close, but not there.

focusing my attention on the accelerator pump, i went ahead and moved the cam to the #2 position because that gave a longer pump but later on in throttle position. i used a .015 feeler gauge to set the accelerator pump lever at it's correct resting position (as per holley). the curve was a lot later to help with that off idle bog. i wouldn't take the timing any further. i'm already running 91octane.

the car ran well. i was almost mad at it. But when that vacuum dropped to 6.5 and the power valve came in, it got real rich real quick. i did some thinking, and figuring that a 50cc shot from the accelerator pump was too much, i began looking at replacing it with the standard 30cc pump. that was too expensive for my cheapness, so i began looking at getting a lower rated power valve, maybe something in the 2.5 or lower bracket. that was also too expensive for me. I began to think "if i was at the track, and only had limited time, no power valves and no accelerator pump, and the atmosphere pressure was a lot less, (i'm currently writing to you @ 510ft above sea level). what would i do?"

i'd bring down the accelerator pump lever so it was resting farther down and make the pump shot less. i debated whether or not this was a good idea, so i started reading the holley book to help supplement my theory. and there it was folks, the text said it all.

the car runs well now. it's good on the street and good on the freeway. maybe if i wanted to spend money i could play with the power valve and get that 30cc accelerator pump, then probably play with the pump discharge nozzles and get it honed in. if i really wanted to i'd then buy a 07448 350cfm metering block and put that in as well.

but all in all i got the carb for $20, the jet kit for $20 and the rebuild kit for $30. not bad for $70. please express your experiences and opinions. i am not the smartest guy out here, so if there's more information we should consume it!

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70 Plymouth Valiant 4dr

Nice list of settings chronicled, but you did not list your engine's build as stock or otherwise.

Every non stock engine has different needs from stock build; there is no one set recipe to follow. Low vacuum conditions, and a lot of cam overlap make carburetor tuning difficult. Drive train design also has effect on tuning as well.

As an example a truck will require different carburetor and other settings than a light car utilizing the same engine build.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I have that book (and the other two Holley books available), and being an experienced holley tuner and have a barrel of stock holley's to work with I will say "watch it"...the series is authored out of the country and some of the info is just wrong...My ultimate favorite is somewhere about page 20 he states that the holley metering block numbers don't match the carb...which is incorrect, if the carb is OEM from a vehicle or new aftermarket the metering block numbers will match the airhorn numbers, if they are mixed and matched or an aftermarket block is used then the numbers will not match...but will give you an insite into what the block came from in case you end up with a Holley 390 cfm carb and a block out of a 650 cfm 4165... (the author also went so far as to "pen in' the airhorn and holley part number on his metering blocks in the pictures which don't match the actual stamp pattern Holley stamps into the metering blocks...).

Lowering the floats in the Holley is similar to down jetting it (so your "actual" jet size may be a few sizes less than what is installed), if the stoich is too lean the vacuum will lessen quickly and the PV will open sooner than desired...Typically the mains will come on line in the stock Holley about 2000 rpm for the right application, it may be required to restrict the high speed air bleed with a piece of wire to get the mains to tip in sooner especially in a light car with a better than stock engine.

That being said and slightly over rich fuel mix will combat engine knock because the excess fuel removes excess heat from the combustion chamber...so check your plugs in all conditions of driving, especially if you are running lots of advance on the highway (which also makes a catch 22 as you can clean up an overly rich condition by dialing in more advance...but that doesn't necessarily mean that you will benefit from the extra fuel wasted or the extra ignition timing).

The book should have told you that the brown cam can only be used with the "Reo" 50cc pump...if you use a different cam, the geometry is a little hinky on the arm, and the pump doesn't work as well requiring a little more mickey mouse engineering (if you want a smaller pump housing and arm...go to the junkyard an pull one from a Holley 4 barrel on an old Chevy).
That's the best setting, any more than that and the slightest overstroke or tromp on the pedal will stress the pump diaphragm and you will have a nice fuel leak out the bottom of the bowl onto your hot engine after the diaphragm ruptures...if the gap is wider you get less stroke and you get delayed actuation.
These aren't non-stick...they will get you by if you put pam on them, or didn't overtighten the fasteners...once the carb heatsoaks for a week of daily driving or the fasteners were overtorqued they'll rip on your next regasket or overhaul...they are much better than the brown or black gaskets on the market...

This is somewhat true, if the carb is set up correctly to properly meter the right amount of fuel it will mostly work if transplanted. If the carb is close to the correct sizing then the settings and some adjustments may need to be made (this is why Mopar could get away with using pretty much the same Holley model on trucks and it's cars with a jet change and an idle mix adjustment), if the carb is too big for the engine it will fall off big time...but I can say that I have installed the good running Holley 8007 off my Hyperpak car onto a 390 and it ran and drove fine with a little tweak to the idle mix screws and a change to the secondary spring...(mileage sure improved too...LOL)... I would not recommend trying a Holley 1945 on a big block without modding the idle circuit and upping the jet...LOL...(but it was fun seeing if it would work...).


2 cents,

-D.Idiot