Idle speed too high.

I have a 512 bb with a Holley 0-80508SA 750CFM ALUMINUM Vacuum Secondary Carb on a run stand. We had it broken in and running well but it had a small oil leak. I fixed the main seal and ran it for 30 minutes today to test for any leaks, none!!!!. However the idle was at 1250 rpms or so. It previously was at 800 or so with 12.5 in hg. I have the idle set screw completely backed out. It has set for about 5 months without being started. Any thoughts, mixture, timing, fuel? Nothing that I know was changed. Did not check the timing or vacuum just yet. I wanted some guidance before changing too much.

Thanks for any help.