Demon Tuning Help!

[jvest]

I just bought a new 750 mechanical secondary speed demon to go on my 383 small block in a 68 Camaro. I did the intial setup with the butterfly settings and idle-eze screw before I installed it. After getting it started and up to temperature, I set the idle mixture screws using the vacuum gauge. I had to run them in a lot, because it was so rich. They're about 1/2 turn out from bottom. I'm reading around 15 on the vacuum gauge. I also set my intial timing to 15 deg. For some reason I have to use the primary butterfly screw to adjust the idle speed. I moved the idle-eze screw from bottom to 4 turns out and it didn't make any change in the idle speed. I'm still preping the car for paint so I've not been able to take it out on the road yet. I've just wacked the throttle in the shop. It sound pretty good when you wack the throttle from a high idle, but is a little stugish (No stumble, just rich) from idle. It also will not start unless I hold the primary butterflies wide open. If you don't, it'll fire off for a 1/2 second then go dead. I had an edelbrock carb on it before this with great throttle response and started up with a bump of the starter, but it loaded up bad at an idle. I know it will be better to get it on the road before I start tuning, I just thought I could tweak on it a little in the shop while I'm tired of block sanding. I listed below info that may help.

Thanks for any help,
Jim

60 over 383 small block with 5.7 rods.
Two valve relief flat top pistons (Eagle Stroker Kit)
Cast iron heads with 2.02/1.60 valve & 64cc chambers.
Edelbrock performer intake.
Standard HEI ignition.
292 Comp hydraulic cam(.501 lift / 110 CL)
Comp roller rockers
15 inhg vacuum at idle (850 RPMs)
3" flow master exhaust with dynamax headers.
floats set at bottom of site glass.
1/2 turn out on the idle mixture screws.
15 intial timing & 38 full advance.
vacuum advance connected to the timed vacuum port per BG tech line (front port).