The engine in this 1999 Dyna I am restoring already had S&S heads and cam gears, also Arlen Ness rockers with Arlen Ness lifter covers so I thought I would go with S&S 97" big bore kit which I did. With cylinders and heads all on I started to install the lifter covers. Whoa up, cylinders not relieved enough for the AN covers. It seems Harley can machine the cyl's to accept aftermarket lifter covers but S&S engineers haven't figured it out yet. Contacted S&S and was assured they were sorry that I had to grind a relief on those expensive cyl's. What the hey, you just tape all openings and spend a lot of time getting aluminum grindings on everything. I suggested to them that the least they could do was include a note with the kit stating that you may have to finish machning the cyl's before use. Better yet, next time I will just use Harley parts. This is just in case any of you were thinking of using these kits. Much better to machine them before installation.