What would cause timing to retard 6-8 degrees under acceleration with a locked out msd distributor and the motor has cam buttons? It is a 350 with a med cam noting to crazy sounds like a chain streaching ?

Or a worn distributor gear.
Let us know what you find.

Brand new msd distributor no problem there I think

Dont know if boats have the same thing as cars, but a knock sensor will retard timing.

no sensors on this motor lol it is a 1980's small block in a race boat

Vertical play in the disributor shaft. Could be caused by worn gear or improper shimming.

What kind of cam? Roller, solid, hyd, hyd roller? I would say it might have chewed up the gear if the gear on the distributor is not for your type of cam. Everytime I have seen chains stretch they have destroyed motors... valves hitting pistons, etc.

Just trying to help a brother out.

Solid cam and lifters and the gear looks fine. It has bronze gear. Set the timing at 42 @idle rev to 4500 it retards to 37-38 Also @ idle you can watch the light back and forth slowly. Hmmmmm

See if the rotor is loose on the shaft under the cap. And are you using an advance light?

Just a wild guess but standard rotating motor and dist they do make counter rotating .