Mercruiser Thunderbolt IV ignition control module v6-14 fits 4.3L 4.3 v6

Mercruiser Thunderbolt IV ignition control module v6-14 fits 4.3L 4.3 v6. Tested on running engine this fit 4.3L engines but some people use them on 7.4l 454 engines to get a different ignition curve.