If I do in fact as I suspect have an N42 block and an N42 head..Can I replace the dished pistons with flattops..? I've been told that if I do it will raise my compression and therefore give me more power..I currently own a 74 260 with an obviously later year l28. The engine has been bored out .020, I think (The former owner wasn't sure how much)and I'm dseperatley seeking more torque..I also believe that I have a second stage cam, SU carbs, and a turbo flywheel. I have no idea how much torque or Hp I currently have but my goal is 200-220 hp..Any ideas..?

Thanks in advance

Yes, you may put the flat top pistons in your block in place of the dished pistons. It is one of the best improvements to an L-28 you can do. It will put your compression up around 9.5:1 to 10:1 depending on whether your head has been shaved, and which head gasket you use.

With the mods you have now, it ought to really wake up the motor. I think you will see a huge improvement with the mods you have now, as you probably aren't gaining as much benefit from them as you would with more compression.

Go for it!