Hi, thanks in advance for any help given.
Holley carb has problem idling. It will idle at 900 RPM or so in neutral and then slowly creep up to about 1400 RPM,stay there for a bit, then slowly back down again, stay there a bit and back up etc. Sometimes it wants to die when it drops down.

About 470 cubic inches with automatic. Around 6 to 8 inches of vacuum at 900 RPM. Timing currently at 26*, but does the same regardless of initial timing. Tried another carb which is a 850 cfm and it idles rock steady with about 10 to 12 inches of vacuum with zero issues. I rebuilt the carb, and tried adjusting as best I could.

Holley HP List #80513
6.5 PV tried different ones and same issue
Jets Prim 79 Sec. 86
Air Bleeds Idle 75 High Speed 25
Squirters Prim. 31 Sec. 36
Secondary Idle transfer slot is "square"
All mixture screws 1 to 1 1/2 turns out

At this point I don't know what else to try. Am I overlooking something. Did something wrong or silly.
Help would be greatly appreciated.

Thanks
Onig