Sorry, but Ive got some more carb questions...  I apologize for continuing to beg for help!

So here is the essence:

Car is a 56 sunliner, 292, ford-o, blue thunder intake, and mummert 270 cam, with 224 duration at .050.  (I mention that since it seems from what Ive read that this is a cutoff on some carbs - i.e. street demon 525 says for cams under 220 deg...)  Engine is healthy - compression was even when last checked (last year), new cap, plugs, wires.  Also has pertronix on a 57 dizzy.

Ive been working with 2 carbs - an edelbrock 500 and a holley 390.  Holley starts easier and has better throttle response (but still has some stumbling and spit back through carb at some points), but edelbrock runs better at wot (as would be expected with more cfm).

1)  Edelbrock carb pulls 11.5 in hg at idle, Holley pulls 7.5 at same RPM.  Does this make sense?  Not sure what this tells me or means, or if "thats just the way it is"

2)  I have been told to check the idle transfer slot on the Holley to make sure that I dont need to drill a small hole in the primary plates.  The transfer slots are covered... but JUST barely.  the throttle blades measure .065" thick, but the most they cover the transfer slot is .028".... just barely... is this enough, or would the hole in the blades help?  I dont want to drill them and have it be wrong... what are the consequences?  I do know that the idle screws dont have a lot of impact on the vaccuum... meaning that it takes a fair bit of adjustment to see a difference.

Right now the holley has 56 primary jets, 62 secondary jets, 3.5 power valve, and a 25 shooter.  Not sure if anything seems out of whack on that or if anyone has any recommendations?

Does any of this make sense?  I am getting really frustrated with trying to get a carb (ANY carb!) to run what I would consider right - easy starts, pulls evenly, without bogs or stumbles, with decent throttle response/mileage (is that oo much to ask???)  I think I wnat to try to get the holley dialed in first, as I dont drag race the thing, and the holley seems easiest to tune/adjust for me to learn on.

Please let me know if there is any more info that would help, or if anyone has any ideas/observations/different starting points?  Im really starting to regret the cam choice!

Ron Grove

Wauconda, IL