Jets are gettin big!

I figuered i had timing rite when i started, (10idle/32max)... Thats what the machine shop said the engine wud prob like.... So i thought it was gettin hot from runnin lean...i put the jets back to 74s and cranked up the dizzy to about 18idle/39max and the temp droped down to 170ish on the next drive.... Now i think i need a dizzy with less of an advance sweep, or even lock it out