95 Merc 350V8 magnum distributor


New member
8 May 2011
South Florida
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My distributor went bad and I want to replace the existing merc dist with a Hi perf chev HEI distributor. Other than setting the mechanical advance curve, dealing with the vacuum advance setup and rewiring the shift cutout switch to work properly is the anything else I should consider? it used to plain out approx 3800RPM, what shpuld the total advance at full throttle be?


Well-known member
30 Nov 2002
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A car type distributor can't be used in a boat, firstly there is no spark protection (a marine distributor has a wire mesh over the venting hole in the base) so there is the risk of explosion if there are petrol fumes around and there always are after turning off a warm boat engine as fuel evaporates from the float chambers. Secondly there is no vac advance on any marine distributor as there is never any vacuum except at idle as the motor is constantly under load and never in high vacuum cruise conditions as in a car.
The max advance is 32 deg at 2400rpm, WOT is 4200-4600rpm or 4400-4800rpm if you have a CD marked engine which means roller lifters.