C172's
you must sell your 172 as soon as possible - why - because it is the N model. That means cams made of something softer than chocolate ready made to spall on the followers. Dont like the idea of one drive feeding both mags either - wheres the redundancy in that. Check your static rpm to see if your valves are lifting all the way but sell it anyway cos it is going to cost and cost and cost..........Never known H2AD engine (lovingly referred to by all as "the Nail") to go past 1200 hours without major work. If you choose to persevere and end up changing the engine put an 0-360 in(its approved) as these , conversely, rarely dont make TBO. I can be trusted on this matter as i blew my brains in on two of these i bought some years ago - both did the same whereupon i had a delve and discovered loads of people had the same problems. Good luck!