bigbang

I've got a 1990 (91?) fairly stock 454 mag. The only upgrade is a slightly larger carb than stock (I think it's Holley dp 750 or so?). It is possible there could have been a mild cam upgrade in the past, but not sure of this (ie. timing cover and intake had been removed at some point and a super nice lopey idle.)

Anyway, boat runs great.........I've never touched the ignition system. I know the thunderbolt is a very good and reliable system. Are there any minor changes to the ignition system that might be recommended (for reliability and/or performance)? What about the coil?

Fuel: 87, 91, 93 octane? Sure get a lot different info on this one.

Thanks!

KWright

A set of moroso spiral core plug wires.

bigbang

Yeah, I've got some high end plug wires on it already.......and I'm running ac r43ts plugs. Didn't know if a different coil would be any better, or if there's anything under the cap that could be improved.

Thanks.

offthefront

iTrader: (1)

If aint broke dont fix it .....if there has not much modifications I would think 91 would be fine ...original Merc specs say you can run 87 .....m

http://www.mercurymarine.com/service...?category=fuel

bigbang

Exactly, you're boat must have been broken when you put pro-charges on it.

Yeah, I think 87 gas can be a bit dicey, since the quality and true octane content from the refinery can vary considerably. At $5 a gallon, what's another 10 cents for better gas.

Rookie

iTrader: (4)

If it is stock I would not change anything with the ignition. If you were spinning 6000RPM then I would consider something else. The thunderbolt is more than adequate and efficient for you setup. Also if you start bumping up the octane in your mag you might have a problem with black soot building up on your transom.

FIXX

iTrader: (2)

the boat had the procharger's on it when he bought it,,he just wanted to go faster then 92 mph!

GTOFFSHORE

You can go to the v6 ignition module. Better timing curve a little better performance.
Also, gas doesn't very. That is just myth. It is actually always higher octane than stated. Don't want to start in that topic but it's established.

MER Performance

Yes, keep the distributor. Buy a Daytona Sensor CD-1 box from Marine Kinetics, I distribute to him. They work with the hall effect system and the box is marine certified comes with a coil and you can program your own curve, set the rev limiter , buy the usb interface kit. Mark