HEI Upgrade?

phatboy454

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Ok guys, I used the search function and was unable to come up with an answer, Didnt bring up anything on the matter in fact. I have a '84 Chris Craft Stinger 260 SL with twin SBC 260hp Mercruisers. I am freshening them up a little this spring with reman Rochesters and am going to do tune ups. Is an HEI Upgrade an issue on a boat application? If not, does anyone have any recommendations for the upgrade? I am not sure if the more "powerful spark" is a dangerous thing in an engine compartment (IE: safety factor??). Any help/insight would be great!. Thank you.
 

bruceb58

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30,530
Re: HEI Upgrade?

If I was going to upgrade distributors, I would use the Delco Voyager EST.

You will see little to no improvement in performance to a properly set up points ignition system.
 

Bondo

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Re: HEI Upgrade?

Ok guys, I used the search function and was unable to come up with an answer, Didnt bring up anything on the matter in fact. I have a '84 Chris Craft Stinger 260 SL with twin SBC 260hp Mercruisers. I am freshening them up a little this spring with reman Rochesters and am going to do tune ups. Is an HEI Upgrade an issue on a boat application? If not, does anyone have any recommendations for the upgrade? I am not sure if the more "powerful spark" is a dangerous thing in an engine compartment (IE: safety factor??). Any help/insight would be great!. Thank you.

Ayuh,.... You should have the T-Bolt IV ignition,.... 1 of the Best that's ever been on the water,....

HEI is a step sideways, or more likely backwards,...
 

phatboy454

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Re: HEI Upgrade?

Ayuh,.... You should have the T-Bolt IV ignition,.... 1 of the Best that's ever been on the water,....

HEI is a step sideways, or more likely backwards,...

Why would yoy say its a step backward? I would think not having to worry about setting points would be a plus
 

Bondo

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Re: HEI Upgrade?

Why would yoy say its a step backward? I would think not having to worry about setting points would be a plus

Ayuh,.... As I said, ya should have the T-Bolt IV now, which don't have points,....

The HEI is an Automotive ignition, 'n don't belong in a boat,...
 

phatboy454

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Re: HEI Upgrade?

Ayuh,.... As I said, ya should have the T-Bolt IV now, which don't have points,....

The HEI is an Automotive ignition, 'n don't belong in a boat,...

Well here is my question for you, The "Thunderbolt Mercruiser Ignition" Is described as and HEI Ignition. Now let me ask the question of why pay $250+ (in most cases more) per distributor when a GM HEI ignition is more or less spelt out the same and half as expensive. So instead of Bashing the GM HEI Ignition and not answering my question, I once again will pose the question of "Is a GM HEI ignition an acceptable upgrade to the points distributor that is currently on my 260HP Mercruisers?"
 

bruceb58

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Re: HEI Upgrade?

"Is a GM HEI ignition an acceptable upgrade to the points distributor that is currently on my 260HP Mercruisers?"
Is it a marine distributor?

If it's this one, then that is a good choice.
5.7L Delco Voyager EST marine electronic distributor kit
It's easy to find parts for and it is the OEM distributor now on many engines.

I have also never seen a GM HEI distributor that is marine. Highly unlikely GM even makes distributors at all anymore.

Surprised a 1984 Mercruiser engine has points.
 
Last edited:

fishrdan

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Jan 25, 2008
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6,989
Re: HEI Upgrade?

Is an HEI Upgrade an issue on a boat application?

Yes, it's not USCG approved for marine engines,,, enclosed engine compartment. Some excess gas fumes, a stray spark from the non-"sparkproof" ignition and the boat blows up.

boat-on-fire-300x225.jpg


Now let me ask the question of why pay $250+ (in most cases more) per distributor when a GM HEI ignition is more or less spelt out the same and half as expensive.

So instead of Bashing the GM HEI Ignition and not answering my question, I once again will pose the question of "Is a GM HEI ignition an acceptable upgrade to the points distributor that is currently on my 260HP Mercruisers?"

The same argument can be made for, why use a marine starter or alternator, when their automotive counterparts are less than 1/2 price. The automotive starter will start the boat and the automotive alternator will charge the battery, but they can also blow up your boat as they are not USCG approved - sparkproof.

Besides the spark issue, the HEI's automotive timing curve is not a "marine" timing curve, and HEI's have vacuum advance which marine distributors do not have. Wrong timing curve means poor performance or possibly a blown engine.

There are reasons why Mercruiser, OMC and Volvo never used the HEI...
 

phatboy454

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Re: HEI Upgrade?

Thank you, I am not trying to be argumentative, I was just lookin for the answer to my question. I dont know for sure if they are points or not, guess I was assuming they were. I have the carbs off right now and plan on doing tuneups etc when I put I back together. Just looking for insight. Thank you
 

MikDee

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Re: HEI Upgrade?

Ayuh,.... You should have the T-Bolt IV ignition,.... 1 of the Best that's ever been on the water,....

HEI is a step sideways, or more likely backwards,...

I agree!
 

NHGuy

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Take off the distributor caps and look under the rotors, if there's a little tone wheel and sensor under each rotor you probably have Mercruiser Thunderbolt IV HEI. I have one and it works flawlessly. The Delco EST is really the only choice unless you want to go deep pockets and get MSD. The reason folks get the Delco is cause it's far less money than Thunderbolt IV, yet it's still non points.
 

phatboy454

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May 1, 2014
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Take off the distributor caps and look under the rotors, if there's a little tone wheel and sensor under each rotor you probably have Mercruiser Thunderbolt IV HEI. I have one and it works flawlessly. The Delco EST is really the only choice unless you want to go deep pockets and get MSD. The reason folks get the Delco is cause it's far less money than Thunderbolt IV, yet it's still non points.


Yeah, I need to look, I have the "gold" caps, I am going to be replacing my valve cover gaskets and putting my new carbs on this weekend. I will check it out then. It would be nice to know what I have. Thank you for the information.
 
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