Watch out for POR 15 products...in my case,either it was a mislabel or it didn't hold color well under heat, but when I got Chrysler blue, it wound up looking more like turquoise after a few weeks of driving.
I wasn't happy with the 2-part epoxy Turquoise I got from Eastwood, either.
I've heard more bad than good on the POR 15 engine paint. I've put some of it on improper application, but I'll bet @Mr C knows how to read directions. Eastwood stuff is kind of hit or miss for me. Lots of big promises, but not always big delivery. I'll say that @commando1 can read directions too, so that really writes those two products off.
I've never heard anything bad on Bill Hirsch paint. I've never tried it though. The only downside is it's all mail order and not cheap.
My personal favorite is the Duplicolor engine enamels. Gotta prime first (again, following directions) and I've been happy with the color and performance. Nice thing is I can buy it from Amazon or down at the local NAPA or Advance Auto with no nonsense. Cheap, easy, and good always works for me.
I've tried other engine enamels with so-so results. Rustoleum engine enamels were the worst, although I love their other paints. VHT is OK, but questionable colors. Their high temp paints work well.