I would suggest caution. I STILL remember a hot 2.5 motor I built back in the 90s. Used the land & sea high compression dual plug heads. Bought the coils locally (non-mercury). One failed and lunched cylinder #1 (it needed BOTH sparks to properly fire and not overheat. I decided to rebuild but scrapped the dual plug heads as too risky. Was careless and just picked 6 coils out of the 12 I had. One was flakey. Very flakey. Finally caught it running on muffs. It was a non-merc coil. Whether they are all like that or not, I dont know.I simply use the “fool me once, shame on you, fool me twice, shame on me.” Critical parts I dont scrimp on.