I have a Lycon built IO-360 with 10:1 compression pistons and I have similar issues.  My engine does not surge and idle, but with stumble, pop and sputter, with the EGT's bouncing all over the place.  It does it shortly after touchdown on any day about 80 degrees, even after a nice long slow descent and gently cooling the engine down from 10,000 feet.  If it sits to get fuel and then restart anywhere up to 3 hours after shutdown, it will idle like crap, but when you put the throttle to it, above 1700 RPM is smooths out.

I have been chasing this problem for 2 years.  I've wrapped the injector lines in firesleeve, had my fuel servo rebuilt twice, the injectors, spider and fuel servo flow matched, changed to colder REM37BY plugs, and I still run into the same problems.  The only thing I can think of is that the hot fuel between the gascolator and the lines running to the servo is getting turbulent in the lines, and not flowing properly through the spider and injectors, hence the EGT's jumping around.  Mixture and boost pump do nothing.  I've rebuilt my mags, new ignition harness, intake gaskets (thinking I had a leak), checked exhaust leaks, etc.  All of those changes and it runs the exact same as the day I bought it.

I now have a new issue of my #1 CHT going sky high on my initial climb out when it never did before.  My CHT's run warm, like any close cowled engine, but mine tries to go above 470 really fast, I have to level off and 500 to 1000 feet and bring the power back to 22 inches and let it cool down.  Then I can add full throttle and it is fine the rest of the climb.  That cylinder has the most airflow of any of them being in the right front. I believe this is fuel related as well.  As cruise my EGT's and CHT's and 20 to 30 degree spread.

Any help would be appreciated as well.

Luke Alcorn