Feedback needed on Porting & Polishing

I've been asked to do an article on Porting & Polishing for The Aviation
Consumer as it pertains to certified engines. Would like some user
feedback, good or bad.

If you have a certified aircraft and had your cylinders Ported and Polished:

- Why did you do it?
- How much did it cost (per cylinder)?
- Did the shop flow match or use a flow bench? ("Don't know" is okay
answer.)
- Did the shop do a fancy valve grind as part of the package?
- If you flew the engine before the change, and if that's all that
changed (i.e. no higher compression pistons) can you tell any
difference in performance? Any WOW! factor?
- How did climb, top speed, cruise speed and fuel burn change?
- Any problems related to P&P? (any cylinder cracking in the head?)
- If the shop worked the valves, did you have any problems with
valves before and are you having any problems now?
- What kind of paperwork, if any, discusses the modification to the
cylinders?
- Was it worth it? Would you do it again?

I would appreciate your input. Please respond to

mppalmer at a o l . c o m

Thanks,

Mike Palmer