With Felpro I've had issues with the overall length of a side gasket being too long & have to cut a snippet out of the center of the gasket (where the heat riser passage is) to shorten it so that the gasket port openings center on the head port openings. just do a quick mockup & go from there. recently had an issue where the gasket port opening (top to bottom) was a fair bit less than the top/bottom dimention of the head port opening & needed some trimming. Luckily not enough to get into the blue "printoseal" border. YMMV I think next time I'm gonna try a different brand as my luck with em seems to be gradually deteriorating. The line ain't been crossed yet but getting a bit too close for comfort & as said there are other brands out there. I might just end up getting a sheet of good material & making my own. HF has hole punches for cheap & they've worked well (stayed sharp) so far. the trick is to use a flat piece of somewhat soft wood under the material you are punching a hole in