Hrnts,

I'd like to add that if you can provide measurements of the engines, then maybe we could give a few other "simple" options. Shimming the sleeve may be an option depending on the current port timing. Knowing the actual head clearance and total shim stack, removing/swaping head shims may give a boost. But without knowing where the numbers are when you begin, any change is simply a shot in the dark.

If you can give me some numbers off of the engines I can tell you where you are and maybe prognosticate the results of some of the "simple" changes offered.

1. head bubble volume 2. head insertion depth 3. shim thickness 4. rod length (c to c) 5. sleeve bore 6. port measurments, exhst/boost/trans (top of sleeve to top of port) 7. TDC (top of sleeve to piston face) 8. BDC (top of sleeve to pistion face). If you need I can talk you through taking the measurements.