fresh rebuild on 408. i been reading up on ignition 101 and was wondering alittle bit as to what can i really need. the new cam in the motor gives me 12 to 13 hg in idle,in gear 10 hg. do i want a can that starts 5-7 hg and is all in at 10. the can on there seems to work thats off my old gto, 16 initial 30-31 with vac manifold attached but the idle up and down as if the can might be for a higher hg. also i tried to get part number 1810 from napa and was told its no longer stocked. so any part number or advice would truely be helpful .thanks