502nova3

Hi I removed my exhaust on my boat and used a borascope to inspect the manifold and found there be quite a bit of rust in them after sitting for the winter I'm wondering how I could tell of I'm getting water reversion or if my manifolds are bad it a 516bbc with dart iron eagle 345cc heads I put on last year as the stock ones were cracked (i know there to big just working with what i had for parts) as u can see from the pics the rust hasent made it to the engine but can see it staring is way into the exhaust port of the head through the valve in Pic no rust on any plugs either. I'm not sure the age of the manifolds but it has a full closed loop cooling system so they have coolant running through them and the risers were replaced at the same time I put the new heads and cam in about 10 hours of running on them at Most. Boat seams to run good it's a 1986 wellcraft nova 3 28ft ran 55mph gps at 4600ish rpm last time I had it out so seams to have good power. Also will manifold spacers help with reversion because i need them any ways as the exhaust seams very close to the water line . cam specs below thanks

flat tappet
Intake Duration at 050 inch Lift:218Exhaust Duration at 050 inch Lift:224Duration at 050 inch Lift:218 int./224 exh.Advertised Intake Duration:262Advertised Exhaust Duration:268Advertised Duration:262 int./268 exh.Intake Valve Lift with Factory Rocker Arm Ratio:0.505 in.Exhaust Valve Lift with Factory Rocker Arm Ratio:0.515 in.Valve Lift with Factory Rocker Arm Ratio:0.505 int./0.515 exh.Lobe Separation (degrees):112

1MOSES1

Any pics of intake or exhaust vslves?

502nova3

yes the second last Pic is the valves with the exhaust slightly open I'm going to pull the manifolds to inspect closer soon but inside of cylinders appear to have no rust and the plugs had no rust