4.3 v6 Timing suggestion

Recently I ordered a few small performance enhancers for the old 1990 4.3L and I’m thinking about ordering a new distributer as well.
My question is what total advance are these engines accepting of above 3000rpm. I’m thinking of ordering a pertronix distributor to maintain the correct timing curve but get more on the top end if these motors will accept it like small blocks do.

For anyone curious the modifications are:
Electronic ignition conversion
4160 600cfm carb tuned specifically for these model marine engines
1998 vortec style cylinder heads casting 113 with a 1.6 exhaust valve
Edelbrock performer intake manifold

Potential enhancers on the horizon are :
Pertronix distributor
Edelbrock rollin’ thunder cam
1.6 ratio rockers
Ls6 .550 beehive valve springs

Current distributor is a mechanical advance and was designed to only advance 12 degrees from idle timing making total advance 18 degrees when idle is timed to spec of 6 degrees.
This is an OMC and don’t not crucify me as I have verified the cams, pistons, and heads are the same as merc. Many more merc enthusiasts are around to have the info I’m looking for.

I think typically you see the 4.3 having less total timing than the 5.7, somewhere around 24 or so With vortec heads .

Due to the load on marine engines they are more detonation prone so comparatively you see marine ignition curves be more conservative in terms of total timing

what you outline should provide a nice increase in hp. the 4 bbl vortec engines are rated at 225 hp. Don’t go nuts with the timing and destroy the engine with detonation.

The 4.3 is in the edge of detonation and the edge of reversion.

The pertronix is a degrade from the thunderbolt ignition

You will need to go to dry exhaust to use the rollin thunder cam. That cam has too much overlap for a marine motor with wet exhaust and you will be suffering from reversion

Being a 1990 OMC, you should focus on eliminating the batwing manifolds

Crummy gasoline. Super hot engine compartment.
Ever heard a boat engine misfire so badly that turning the key off of a carbed engine. Did NOTHING to the CONTINUOS violent miss firing of the engine. Called Dieseling. My 5.0L did it 1 time on a very hot and humid day after a long WOT run. Regular gas DOES NOT work in hot weather.

I have the same engine, I have thought about upgrading to an electronic distributor but was always concerned about what the advance curve for them would be, given the way they were set up by OMC the advance curve was so ultra conservative. Points are OK on marine engines that don't get a lot of hrs on them, they can last a surprisingly long time. Also if you go to an electronic distributor with the OMC Cobra you may need to change the ESA module for one that works with electronic ignition. CDI Electronics does make them. I'd like to use a GM EST distributor but I'd want to know what the advance curve on it was before spending the cash.
If you wanted to get rid of the batwings, I've done it, it can be done with a mix of Barr Marine aftermarket manifolds & elbows and Volvo Penta 90* down pipes and rubber exhaust hoses. It basically fit perfect with no leaks. The Barr kit is a lot less than Volvo OEM, and you can find those 90* down pipes used from freshwater regions, do not have to buy them new, they are pretty expensive. Actually this system was designed by OMC before they got bought out by Volvo, who just kept using it till the more modern engines came out....

Very little spark advance is a great way to very rapidly build up carbon in a engine.

Just thinking about this, does anyone know of an aftermarket knock sensor kit? Seems pretty easy to use a stock sensor with a buzzer or something on it...
It would be cool to actually be able to dial in timing and fuel mixture based on something better than feelings.