Hey Mad,

Have you tried a higher octane fuel? Like 92? You can get pre-det from a number of things, like too advanced timing, burned valves, low octane fuel...and so on. If you run a heavy vehicle, that can affect timing also. If you think you've damaged something, look for the smoke.

Re the pistons...it can be difficult to tell what they are. A cast piston is typically dull grey (like the background on this post). A forged is often shiny silver and generally you can see machine marks cut into the top. In either case, if you're not in the racing business, cast will work just fine. Either can have the eyebrows.

Good luck,

tj