Rybad- The marine section on p.20 of the Pertronix Ignition Catalog indicates their Ignitor II conversion module kit # 9ML-181 should be appropriate for a 1987 Crusader engine ( all models with Mallory distributor). You can call them to confirm for your engines /distributors.
http://www.pertronix.com/catalogs/pdf/ptx/2015/Pertronix2015.pdf
I haven't used the Pertronix conversion kits, but I strongly recommend the more robust (red) Ignitor II model rather than the original (black) Ignitor , as the former lets you get rid of the sometimes troublesome original ballast resistor .
Plus, very important, the Ignitor II reportedly does not burn out like the original Ignitor when the ignition is On but engine Off for more than a few minutes, as often the case when chasing ignition or other electrical gremlins.
You may want to get their recommended coil too to make sure everything works best together.
The Pertonix (and I believe the less-common Mallory) conversion kits still employ the mechanical advance under the breaker plate I believe, so that would still have to be in good maintained shape.
Consider, if just converting , only the points and condenser ( & externally the ballast resistor) are replaced. You still have a 30 yr old distributor. That's not necessarily bad, but...
You did say you aren't interested in actually replacing the distributor, ....but before you buy the conversion kit, I suggest you grab the rotor or rotor shaft and see if there is any side-to-side movement possible in any direction except rotary. If so the shaft is worn as their should be none .
Another clue indicating worn shaft is if the analog tach gauge needle acts at all "nervous" at idle. If either of those are seen , it would be wise to consider a new distributor.
I had 1988 Crusader 270 hp 350 c.i. engines with points, condensers, ballast resistors and mechanical advance that were getting to be a PIA each season , and the tachs were nervous & I could discern some little sideways play in the rotor shaft.
I talked to the head engine tech at Crusader headquarters and he HIGHLY recommended swapping out for the Delco Voyager EST full-electonic distributor kits , which include the matching coil and new quality plug and coil cable set. I had my boat's winter yard install those and I never had ANY distributor trouble for the next 8 or so years I had those engines.
The distributors are all electronic including advance and have no mechanical advance. Just set base timing ( 10*BTDC?).
Those kits are superb from my experience and to me well worth every penny, which is not that much more than the conversion module kits if you add new cables and coil. The yard had installed over 100 Voyager EST kits back then with no complaints.
Just in case, here's one place that carries them :
http://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-119.html That's for standard LH CCW-rotation engines.
I think marineparts may have them as well.(There is a separate model for opposite RH rotation engines .)
That said ( once again) , an awful lot of boaters have had great luck with the Pertronix conversions if their old distributor was not worn. especially using the better Ignitor II.
