The only gasket maker would be on the china walls on the ends which wouldnt cause a vacuum leak (an oil leak, however not a vacuum leak.
should not be any gasket maker on the head to manifold connection.
Wow I was just thinking about something with this carb. The new base gasket they gave me at boat store looks different the original I had on there first pic is old one, second pic is new. Is this probably causing my issue with it not idleing at correct rpms?
Yes I used gasket maker on the china walls. Were is vac leak likely coming from then? carb?
you have to find the vac leak. I use a combination of an unlit propane torch and a can of carb cleaner to find a vac leak. however the drop in RPM by 500 sounds like either fuel delivery, or carb issues.
when was the last time you replaced the water separator filter? did you inspect its contents?
is your 86 still points? or TB IV?
spun rod bearing would be knocking like someone smacking your motor with a 10# hammer
what issues are you having setting the base timing?