Low RPM stumble

Using my rule of thumb, the target idle-timing needs to be about 22* to 27*;starter kick-back being the limiting factor.
On Holley type carbs,the accelerator pump freeplay needs to be readjusted after nearly every idle speed adjustment.
With the new idle-timing, it may be possible to close the primaries to get a better transfer port sync-up. Put a vacuum gauge on the spark port. Crank the primaries closed until the sparkport reads less than 2 to 4 inches vacuum. Then set the idle speed with the secondary cracking screw. Reset your idle mixture screws for best idle quality. Reset the accelerator pump freeplay(s). That 245cam should be ok with the standard A-pump, but all the checks need to be in there, and with 2.76s will need a pretty good shot to get going at low revs.

2.76s with a 245 cam! Are you serious? You cant really expect to tune that very well.Wait til the 4.10s are in there and a hi-stall. Everything will magically come together!