Any Carb Gurus out there want to comment?

[Pman1961]

Motor 445 sbf, 611hp@5900 with 750SS Quick Fuel DP mechanical secondaries carb, Brodix 210KC heads, victor jr. style intake, 10.4.1 comp, hydraulic roller .609 lift intake, exhaust, 254 intake 262 exhaust @ .050, 104 intake centerline, 108 lobe seperation, 9 inches of vacuum at 1,000rpm idle, msd ignition, TKO 600, 3:46 gears, Superformance Cobra. Okay currently it has a Super Street Quick Fuel 750 dp mechanical secondaries which was used on a 408. Motor likes and needs a lot of initial timing. With my primaries set showing about .020 of transfer lot at the bottom of the primary throttle plate and not adjusting the secondaries it idles decent at 26 degrees initial advance. Car cranks up fine at 34 degrees initial and seems to run decent at idle as well. Go any lower in timing I have to adjust the secondaries to get it to idle. Also, when I run a lower initial timing even at 20 degrees I get a little stumble off idle. I can take care of the advance limiting situation but I do have an issue with the air/fuel idle mixture screws. The screws are currently 1 full turn out. Turn about a 1/4 in the motor will lean and begin to drop idle. However, when you turn the mixture screws out it seems to have no effect. I'm sure it is an air bleed size issue but I have a question. With the motor description I have given would it not be better to use a race style carb such as the Quick Fuel 'Q' or Race 'Q' and increase cfm to 850? I've been fighting the cam with the timing and carb. Getting close but I want to see if anyone out there is running a race style carb and working well. I don't know if is worth retuning my carb if I would have been better off with a race style carb in the first place. Thoughts???