This has been covered a few times before and you should be able to bring those old threads up using the search function. I had it done for a customer's plane (a 1972 7GBC) while the engine was being overhauled by LyCon Aircraft Engines in Visalia, CA. It is most definitely worth doing. We also had the higher compression pistons installed, which makes it a 160HP (100 octane) engine. When dynoed during ground run it prouced just over 180 hp. Having flown the airplane myself before and after the work, the difference is obvious. The performance is much better than we expected. There is no change in TBO, it's done under LyCon's STC, and as far as I can tell there is no downside. There are others that hold STC approval for the same type work. It isn't rocket science, just old school flow dynamics technology. It's easy to make these engines breathe better because in stock form they are so bad. Do it!
Hag
