Drilling Holes In Carb Throttle Plate Blades

Sorry, a lot of NONSENSE in post #11. If the engine has a sizable cam, & it sounds like it does, it will want a LOOOOOT more than 12-14* of initial timing. Also nonsense to claim that a lot of idle timing causes a bang [ rpm drop ] going from N into gear. Just the opposite will occur: there will be less rpm drop & shift will be smoother.

Reason is quite simple: when you increase idle timing, idle rpm increases. The increase is because the engine is making more hp. When placed in gear, the tq c'ter loads the engine & rpm drops. With the engine making more hp from the extra timing, it is better able to carry the load & the rpm drop is less. GM engines used manifold vac adv, which added timing at idle. My GTO left the showroom idling with 26*. It now has 48* at idle with the big cam, has a smooth idle & enough vac for p/brakes.

More info here, post #6.

www.hotrodders.com/forum/vacuum-advance-hooked-up-directly-manifold-bad-47495.html