Well I hope the weather hasn't been too harsh for ya so far. It's getin colder and darker every day here. I've already managed to catch strep throat now so I'm out of work for today. I guess it takes a real nasty sickness to finally slow me down! I've been on a roll these last few weeks gettin all my projects squared and Now I'm dead ended with a nasty sore throat. I hope you've been able to catch up on your things!

Anyhow, down to business. Last tuesday I was able to sneak out and toy with my car a bit after work. I took th timing light, 3 vaccum gauges and a wad of handtools to my "Moto Shade" shop I have erected in my backyard for the time being. (Looks like tent-city in Saudi -lol) Anyhow here are my setups and also my findings:

I have 2 holley #9776 Manual Secondary 4160 model carbs without choke setups. Each carb only has 1 vacuum port which comes from the primary metering block on the passenger side of the carb. This vacuum port seems to read manifold vacuum rather than "ported" vacuum as most all holleys do. I have a C4 Auto trans. The carbs are currently jetted with #54's (came with 58's when I got them) and of course has a non-adjustable metering plate in the back. I increased the accelerator pump squiters to #37's to take care of an off idle stumble. (was originally #31's) The powervalves are 3.5's which I didn't do, the previous owner i bought the setup from changed those from 8.5's. The setup was only a few weeks old when I bought it. Not really sure WHY he took it off his car. All i know is that his engine was built even bigger then mine not to mention a 302. The carbs are set up to open together. I'll also include pics of my setup to help you to "see" what we're dealing with.

After it was all up to temperature, it sat at idle of 1200 rpms in "park" and the timing was at that point already set at 30* initial. Yeah I know....ALOT of advance. It never pinged, not once. I had 13" of vacuum at each of the carbs and 12" at the back of the upper plenum which is where my vacuum taps are at for my power brakes and tranny modulator. The PCV valve is tapped centrally into the underside of the upper plenum between the carbs.
Now when i put it into drive, the vacuum drops to 7" at both the carbs and the manifold. It refuses to idle steadily at all below 800 RPMs. It will literally "thrash around" if you try to go less than 800 kinda like you'd be starving it of air.
Now I tried playing with it a little bit. It doesn't seem too picky at the initial timing setting. So I rocked it back to 14* and idled it back up to 1050 Rpm rather than 1200. It was pulling 10" at both the manifold and carbs while in "park." I tried to put it into drive and because it was below 800 Rpms, it was idleing erattically, as in from 500-800 bouncing continusly and occasionally trying to die which I'd tap the gas a bit to keep it alive.
One thing I did notice is that when I put the timing light on it, I ran it up to 3500 to see how far it's advance..... well.... it didn't even move.... yeah BIG red flag there. Tore of fthe cap, anf the mech advance is operating fine. moves freely and springs back. So I put it back together and tried it again.... same crap. So i took the distributor out only to pull the damn ARP drive rod out as well (SON-OF-A-@&*@$&) and took the distributor into the shop and took out the Pertronix unit and pulled the advance plate out. All the weights and springs all look good and function fine....what gives there?
Oh and another thing I noticed, when I was throttling the carbs (i had two of the exact same vacuum gauges, both only weeks old bought at Sears on the carbs) the front carb made a more erratic sweep on the gauge than the rear carb and the rear carb was sluggigh to return to the front carbs' idle vacuum when letting go of the throttle. The rear carb didn't have nearly the vacuum sweep the front carb did at all. Kinda weird isn't it?
Also i played witht he PCV being hooked up or not. I really didn't have any effect to the manifold vacuum (at idle in park) when it was hooked or unhooked and plugged.
You made a note of hooking up the vac advance on the carbs. Well when i do that it seems to prematurely advance the timing and when it's throttled it actually retards momentarily. I think that method only works for Chevys and a few Mopars but on fords, you just can have the vac advance pulling at idle.

Anyhow, it's a load of info. I hope I gave you some useful stuff to help you help me on my carb nightmare i'm having! No real rush on the reply. I can understand you're a busy man. Just when you get a chance, perhaps on a cold rainy night.