I recently rebuilt my A15 and added an overlap cam, high lift, 264 duration. Duel webbers, dcoe 40, now I can't even get 710"hg vacuum to run my vacuum advance... I tied the runners together for a common vacuum port. Vacuum Gage shows shows max 10" hg and shows a late exhaust valve close? Won't even activate the vacuum advance, runs pretty good otherwise... any advice? Look up instagram for pics or build, or my profile on facebook...