As part of my restoration I’ve had to recowl and rebaffle my engine. It is a serious Frankenstein engine….an O-290-D2 with angle valve cylinders. It is overhauled by a reputable local shop, so I want to stick with the engine. The cylinders are simply very “tall”. The original cowl had an interference fit with the cowl…they simply added some rubber to the cowl and let it touch. In reworking the cowl, I’ve spent a lot of time making sure I have positive clearance, but it is very minimal…less than 1/4” at the baffle bosses. I have rather large gill openings already to get this minimal clearance. I know that conical mounts keep the engine stiff. It seems that there is very limited rotational movement as compared to dynofocals. Does anybody have quantified data on engine movement with conical mounts?