Smart man :-)
These are the ones I run .

https://www.holley.com/products/igni.../parts/556-112

can't go wrong w/ these coils,,they pack a punch and don't require more than 4.5msec of dwell.

I agree with Sutpen 30, these are the coils I use with my MEFI 4B and they do pack a punch!

Dan, do I need any other harnesses besides the 558-312? https://www.holley.com/products/igni.../parts/558-312
They mention 558-307.
Also, I commented on your post in the "Classic Offshore" section "Post Your Oldschool Ride". I had no clue... You man, are a miracle worker.
Those are the coils I have in my cart now. I was going to post them in the morning. I guess you guys beat me to it.

https://cimg3.ibsrv.net/gimg/www.off...d6ab43bdce.jpg
That`s my wiring parts list, you`ll need the 307, it plugs into the 312 ( I`m pretty sure I remember that right) There will be some changes to that harness, mostly you`ll be cutting out the 18 gauge wire and going with something in the 10 gauge. Then you`ll be tying some wires together and running one single ground to the head and another ground to the battery . (pins C and D) take care to look that over well... I remember the directions and colors were confusing .

307 harness
PIN C:


https://cimg1.ibsrv.net/gimg/www.off...8ec58d1eb3.jpg


All the reds and browns go together to a single source :

https://cimg3.ibsrv.net/gimg/www.off...281dc8cded.jpg

I think this was the Pin B ground:


https://cimg4.ibsrv.net/gimg/www.off...122347783a.jpg

You`ll also need a coil relay.



https://cimg3.ibsrv.net/gimg/www.off...04a466d9cb.jpg


I fused it using this one :


https://cimg9.ibsrv.net/gimg/www.off...e5c25e5425.jpg
https://cimg1.ibsrv.net/gimg/www.off...30540139c9.jpg


I needed a few more spots for grounds and power this came in handy :

https://cimg1.ibsrv.net/gimg/www.off...419dc6488f.jpg

One more bit of advice is go to your print shop and have them blow up the instructions. Hang em somewhere.
You can thank me later after you see how tiny the included instructions are .


https://cimg2.ibsrv.net/gimg/www.off...54034a348f.jpg
https://cimg5.ibsrv.net/gimg/www.off...e839567987.jpg

Used those to prevent any interference , lots of electrical stuff in close proximity back of the engine.

Thanks for all of that information!
I see a lot of guys on YouTube with instructions blown up. I believe that is there first thing they tell you to do.