Have a 6-71 on a 383 with Track 1 heads and 9.o compression, 8 psi boost, 32 degrees timing, 2-750 QFT carbs, mild cam, 1 degree timing out per pound of boost. Originally dyno'd @ just under 600HP running Holley 650 blower carbs with choke horns. Tried dialing in the new carbs just for a good baseline idle but noticed when you hide some light from the coated headers they were glowing a dim red. Richened it up a 1/4 turn on all the idle screws, started idling ruff and running rich. The idle screws started out 3/4 out from bottom with a good idle to 1 turn with a ruff rich idle. How sensitive are these blowers to tune at idle? Is the dim header glow from being too lean? The QFT carb have 74/84 jetting with power valves in the primary's and 31 high speed air bleeds. How close will these "out-of-the-box" carbs be? They seem very responsive but sure seem very sensitive as they huff a pretty rich mixture out the tail pipes when you snap the throttle up to 4500. They only have 30cc accelerator pump compared to the 50cc's that used to be on the 650's. Also have a Boost cooler that needs dialed in. Boost Cooler claims the boost AFR needs leaned out to 12.0 in order for the cooler to work right and make power with the added timing you are suppose to be able to add back in. Any tips would be appreciated.