Pat and Sue,
Believe it or not Albert's two year old IV-P is still in Tehachapi and just sitting with 40.1 hrs.  It is a big hit here at our little airport as it is so beautiful.  So, to the point... I did a cooling mod about 18 months ago. I put a box around #2 cyl and instead of building another, or making a hole, in front of #5 I put in a shim of 1/8" HDPE to allow air around the valve area.  All CHT's are within 25 degrees F if memory serves.  A great improvement over the stock baffling on the factory fast build engine.
Can you fill me in on the lower cylinder ducts?  I am curious (green).  I have shielded the lower cowl from turbo heat but would like to know about that and exhaust shields, too.  Is that info proprietary from George?
Thanks,
Walter Dodson  LIV-449
ps: Albert and Orin will be here in December to try again at training and also to move 90Y to Chicago.
I may go along and see a show at Albert's Goodman Theater.  Boy, if he had a feather...
Walter Dodson  LIV-449
ps:  How many trips across the US is in that 500 hours on Papa Bravo?