Confused / Question about HEI distributor

[TheMayor]

Hey guys looking for some help based on your experiences. I have a 21-foot Cheyenne Day Cruiser running a Harman Marine 330 HP 454 and Berk JG pump. The original distributor has been replaced with a stock GM HEI from a car motor (vacuum advance). I have the vacuum advance capped off; does the distributor still advance normally using the centrifugal weights assuming it has them? Does a marine distributor have different advance curve compared to a car distributor? Should I replace it?

[celeb1]

That HEI will work perfectly fine but you may want to check into coastgaurd approval on it, I think what they are looking for is screens to keep sparks from jumping out of it. You can use different springs to custom taylor your advance and you can buy a high performance coil and module.

[OLDRAT]

If the motor is not in an enclosed compartment there should not be a difference. You can buy a lockout plate to replace the vac advance or secure it, then curve the distributor. You can get a high output coil and module to improve the spark also. I set my curve at 24° at 3000 rpm and then added static timing to that figure (10°) which equals 34° total.
If it is enclosed, you should consider getting a marine approved distributor (which consists of some vent holes and brass screen)
Check out www.performancedistributors.com, they have parts and complete distributors for marine use, and are great people to deal with.
OR

[TheMayor]

Great information and feedback. The engine compartment is enclosed and I should replace the distributor with a marine grade unit. I like the low maintenance of the HEI and was looking at the MSD web site and see they have a Chevrolet Marine Ready-to-Run Pro-Billet Distributors, that states it has a maintenance- free magnetic pickup. Does this mean there are no points (require setting points and dwell), or would this be considered maintenance free as a HEI?

[MANIC MECHANIC]

I have a mallory dual point marine distibutor.
Is there a kit to convert it to electronic ?
:confused:
Tim

[fourspeednup]

Originally posted by TheMayor
Great information and feedback. The engine compartment is enclosed and I should replace the distributor with a marine grade unit. I like the low maintenance of the HEI and was looking at the MSD web site and see they have a Chevrolet Marine Ready-to-Run Pro-Billet Distributors, that states it has a maintenance- free magnetic pickup. Does this mean there are no points (require setting points and dwell), or would this be considered maintenance free as a HEI?
MSD pro-billet has no points, so long as you get the marine version you're good to go. The regular one I've heard corrodes real bad in a wet environment.

[HP350SC]

The marine one corrodes like a POS too. First year I had one internals corroded all up. Cleaned it all up in Spring. Next year same thing, so I disassembled it and cleaned it all up and painted the pieces that corrode. Shouldn't have to do that IMO.
I have said this before but I'll say it again, a stock Merc. distributor is superior. Hall effect trigger which is better than MSD's magnetic trigger. Combined with a Crane HI-6M and coil you can't beat it. Crane is fully digital w/built in adj. rev limiter, boost retard, 6 or 7 different advance curves all tailored to Mercruiser blown or unblown motors. Also has built in diagnostics.
Plugs right in w/matching color weatherpack connectors. Only downside is you have to re-index the rotor on distributor which is drilling 3 holes and moving shutter wheel.

[Fired Up]

A small bit of advice...get the MSD rotor with the brass center terminal. The stock one will melt like a marshmallow with an upgraded ignition. Cheap performance investment. I run the Crane Hi-6 in my flattie.