Originally Posted by ggevaert
Took carb off (holley streetfire pn 8362) to ensure the transfer slot was ok and adjusted the primary transfer slot to be 0.020. (was at 0.040)
then I noticed that the secondary was totally closed. (i.e. no transfer showing at all)
In a vacuum secondary do you need to have the transfer slot showing at all?
0.020"-0.040" is the baseline setting (about square, or open as far as the slot is wide). It is not at all unusual or incorrect to have the primary transfer slot at 0.040"- in fact that's more common than less if there's any kind of performance cam involved. The baseline for the secondaries is almost closed, then open as needed to get "bypass" air.
The initial timing has a lot to do w/this as well- if there's not enough initial timing, the transfer slot will almost always end up overexposed, and the idle quality and off idle response will suffer as a result.
The goal on setting the initial timing as it relates to the carb's transfer slot is to find the correct amount that will allow a clean idle without the carb primary butterflies needing to be opened so far at idle that the transition slot becomes over-exposed. This condition will cause a stinky "rich smelling" exhaust (it actually is unburned hydrocarbons, not necessarily too rich). It will also cause a poor quality idle, nozzle drip and poor transition off-idle.