Idle Issues

Robbie2734 said
If it started out idling at 900 and then jumped to 1500 after a few weeks and nothing was changIed I would look for a vacuum leak.

XS2. it could also be something going on with your vacuum advance (if you are using it)

i have a 600 holley on my charger using a 284/480 cam and a 2800 stall converter and it idles at 1250 and 700 in gear