I spoke with my engine builder today and said they did the break in on my engine yesterday. They recomended my distributor be replaced as they said it appeared to have slop and wear. Any reccomendations and prices, full ignition package? Should have my build sheet in a few days....had a few surprises in the tear down, mainly mismatched parts, non matched casting etc.

I have used the mallory marine unit with good results

What ignition do you have now???? The stock merc TB IV is a very good reliable set up and should be just fine for what you had built.

The Mallory Marine magnetic pickup is a great choice if you are running a carb, very simple and reliable. about $255 @jegs/ summit

If you have the MPI then rebuild or replace the merc thunderbolt unit, the ecu needs control of the ignition for multiple reasons

It's a carb engine with a thunderbolt. Is MSD the same as Mallory? My engine builder told me he ordered a part for a thunderbolt the other day and Mercury told him they werent making the thunderbolts anymore. He liked the thunderbolts but thought it was odd to phase them out advised there could be a problem getting parts in the future.

MSD is not the same as Mallory. MSD does make a nice "ready to run" marine distributor like the Mallory but Mallory parts are more readily available.