Changing to HEI ignition on a 1991 mercruiser 5.0

[oldbouy]

hello , I am updating to HEI ignition , researching how to complete this has been confusing .
the current ignition system is in good shape . I bought this used last year , my question is , do I buy pass the ignition amplifier ? do I need to replace and upgrade my spark plug wires ?
do I need to widen the gap on the spark plugs ? do I need to reset the timing to 8
degrees before top dead center ?
I am using an A-Team performance HEI distributor with a 65k coil enclosed . thank you for looking at this request .

 

[Scott Danforth]

HEI is a designation for GM's electronic ignition that came out in 1973.

its not an upgrade compared to the thunderbolt ignition

I would suggest something higher quality than something off of amazon such as the A-team distributor.

get the delco EST marine setup that has been proven on mercruiser installations with the alpha drive because you need to interact with the shift interrupt switch.

 

[Scott06]

hello , I am updating to HEI ignition , researching how to complete this has been confusing .
the current ignition system is in good shape . I bought this used last year , my question is , do I buy pass the ignition amplifier ? do I need to replace and upgrade my spark plug wires ?
do I need to widen the gap on the spark plugs ? do I need to reset the timing to 8
degrees before top dead center ?
I am using an A-Team performance HEI distributor with a 65k coil enclosed . thank you for looking at this request .

IF the current ignition is in good shape why are you replacing? Since you say amplifier I assume you have Thunderbolt 4 ? If so you wont gain anything and likely loose reliability with offshore stuff.

Only reason to replace wires is if they dont fit new system or you have high ohms and they are worn out.

Spark plug gap is determined by what the ignition system recommends. Not familiar with A team so I would ask them.

Yes will will need to reset the timing after swapping in a new distributor.

Lastly is the A team HEI marine rated ? there is a difference between marine and auto for electrical components

 

[matt167]

A team does make a marine rated HEI now, for a little under $200 BUT it’s a Chinese HEI that is modified. I don’t even think it’s actually rated. There is no other support for it. Not something I’d do