Did you check PTV clearance on the new set up? I know you said you bore scoped it and all…but it’d be good to be sure.
Also, what cam were you running on the 318? Did you degree it? My Victors have almost .200 valve drop (don’t remember exactly at the moment) on the exhaust…that exhaust timing event would have to be pretty far past TDC, especially with the valves laid more towards vertical, where you gain some clearance (hence the decent valve drop numbers). Bit of a head scratcher (see what he did there..?)