Vaccuum advance

[baja ja]

My dizzy went south. Got a bbc chevy hei with vaccuum advance. what are the pros and cons to using this with my 454 indmar

[sleekcrafter]

IMO GM HEI are junk units for performance marine use. Pertronix make a nice elctronic module conversion for marine dizzy's. No useful purpose for vacuum advance in boats, in cruise it advances the timing excessive, and can melt down pistons as a result.

[KonaKustoms]

I like springs on a mechanical but vac works, nothing wrong with vac except for jet boats pull hard and take a lot of carb to run rite and there is always vac changes while running so i run a sprin advance unilite mallory with a mds box for rev limiter and a little more fire.
I like a clean running motor and vac changes alot on a jet setup in anything but smooth water .
Study how each system works and it is real easy to see the pro's and downs on each!!

[Fearless]

get the distributor tuning kit from summit. you can swap out springs and diaphragms and weights to tune your timing curve. realistically, why not grab a marine msd setup?

[racer]

Not to mention that distributor is NOT uscg approved

[KonaKustoms]

if its open engine it's fine and just do a spring kit and trash the vac junk!!

[Fonz69]

have a guy here locally that has run a GM HEI for years no problem in a 21 daytona with a 454

No Vac advance and he runs a upgraded coil but I have been in the boat with him cruising at 5800 rpm for miles at a time down the river

[TIMINATOR]

HEIs and other car dists.(even those performance units) have an incorrect advance curve for marine use. Always have any boat dists set-up by someone who has a dist machine and KNOWS what a boat needs. Prop boats and jets require different curves also. P.M. me for further info. TIMINATOR

[KonaKustoms]

Yes u are rite, a boat has a different curve for timing but also has to do with alot of other parts also.