your monitor is a Wells-Gardner K7000.
the curling issue at the top is a very common problem, and it seems to vary with different games. it's generally fixed by adjusting the 50/60 Hz pot.
now I'm no scholar on the subject, but if I'm understanding this correctly, you adjust this pot to match whatever the vertical refresh frequency is... I say this because I pulled a K7000 chassis from a Suzuka 8 Hours 2 and it had no curl effect and as soon as I ported it over to Mortal Kombat 2, it exhibits the same curling you have. lots of games run at 60 Hz vertical refresh... Mortal Kombat 2 on the other hand runs at about 53 Hz.
it's not very noticeable in-game for me, and the chassis is kind of a loaner one, so I didn't tinker with the 50/60 pot, but of course it will stick out like a sore thumb on a crosshatch pattern.
there are some games that you CANNOT adjust the curl out of, to my understanding a lot of Neo-Geo games have this problem. the solution? I don't know if one exists.
in your case though, I'm thinking maybe you should try the 50/60 Hz pot first, to see if it'll adjust out. if not, then you'll have to just live with it I suppose.
speaking of monitor tweaks, make sure your brightness is turned down enough to where you can't see the grey or brown pixels against a black background. you shouldn't see pixels in black, black should be pitch black.

if for whatever reason you can't adjust the brightness down the way I suggest with just the brightness pot, then you'll have to slightly turn the Screen pot on the flyback down to give yourself more adjustment room.
your contrast should be turned up high enough to where you don't get any "smearing" or blooming effects (probably not the best term, blooming in monitors is something else..), it's done best on a screen with text, generally like a test mode screen... just turn the contrast up and down for comparison purposes and turn it up high enough before the smear or the letters blur bigger.
you may or may not have known this, but I figure I'll throw that out anyway.
also once you make all the brightness/contrast adjustments, then you can adjust the focus. if you can't get it to focus, then your contrast may be turned up too high, it'll create a similar effect to poor focus.
that's all. if you have any other questions feel free to PM me. there's a K7000 sticky thread, I encourage you check it out just to read about common problems and fixes.