I am replacing my TB IV with a HEI dist with the Vacuum adv removed and wondered how much the mechanical advance gives on a stock Distributor.My vortec heads only need 29 deg total and I'm running a little more compression and cam than stock so was hoping for 12 or so initial with 29-30 total.

I think HEI has 24 degrees built in.

HEI's not explosion proof.

Be sure to wear Nomex when you drive it.

If it's not a marine distributor, DON'T RUN IT!!!

Why are you replacing the excellent Thunderbolt ignition?

Thunderbolt is a good dependable ignition system. Definetly dont put a car distributor in your boat for obvious reasons.

Do Not Put An Automotive Dist. In Your Boat!!! Call Teague Custom Marine Get The Msd Dist., Hei Box And Coil. Use The Two Light Blue Springs W/ The Black Advance Bushing And 12 Degrees Initial For A 34 Total Advance.

Be sure and get the marine version upgraded HEI if you are going to run one.

I have had good luck with DUI in Memphis www.performancedistributors.com

Just my .02

OR

My understanding of a Marine approve HEI dist is that the distributor base has screens to prevent sparks from jumping out. DUI is the way to go, I think all of their distis have the screen in the base.

Why can't I put a screen on my HEI? I'm sure they don't cast their own caps. Guess I've been lucky in the past, I've ran for yrs with Reg HEI,carbs,(starters too most likely,(how can you differntiate on the starters?)). Thanks for all the input, I do have a little more fear now as I grow up .I'll screen it or resell it.Anyone willing to sell me an hp 20 deg module?