Jpswino: I am sure the heat from either the prebaking or the powdercoating temperatures will affect the engine castings in some way. They may or may not distort. The temperature may or may not change the structure elements of the aluminum itself. I really don't know. Personally, I would not powdercoat the engine cases. Powdercoating the covers is quite easy to do.....but even some covers that have had oil in them can be a real pain. Example: One oil pan I just did (1.) scrubbed clean with solvent (2.) sandblast (3.) compressed air blow (4.) clean with brakeclean (5.) compressed air blow (6.) prebake in oven 450 for 4 hrs (7.) sandblast again(to remove the burnt on oil residue that comes thru the casting) (8.) compressed air blow (9.) clean with brakeclean again (10.) compressed air blow (11.) propane torch burn (gets rid of any small fibers stuck in the aluminum) (12.) brakeclean once more (13.) blow down once more (14.) now you can do the 20 minute powdercoat!! If you are not happy with the way the coating turned out.....well...you have to start with some aircraft stripper, plus all the steps previous!!!!

Just a footnote; I completly dissasembled a set of carbs on my 550 and powdercoated them. Two of the four carbs warped or changed enough that I had to do a couple of hours of lapping to fit the slides back in.