timed vacuum vs manifold vacuum

Its up there 5000+. Engine still wants to pull. The ignition system is new put there by me (orange box kit). The cam and springs were not done by me so maybe the springs are tired. That is something to think about for sure. Its a mild solid 20-246-4 Comp cams .468 lift. I know the springs were for the kit. Looks like its not a simple fix.