The term "Re-Worked" is the problem inmost cases. I have said before, of all the engines that I have gotten from Tom Lay, that were what a lot of people would call "reworked", were just more of a dedicated set up and maximizing fits than anything else. Tom never retimed anything I got from him, just installed a venturi, checked bearings, made sure of piston/liner/piston ring fit. His venturis were restrictor style, which required the case to be drilled on some Super Tigers. He would heat treat pistons and rings for better wear and seal. But if you had just installed the engine in an airplane with factory venturi set up, and fed it proper fuel, it would have performed satisfactorily for most pilots. I have neve run a "reworked" LA.46 because I can get them to run well stock out of the box. Same with the LA.40 and the FP-40. The Hemi head is something that guys like, and it gives a certain sound to the run I think, but in of itself I don't think it's a game changer, but when used with some other changes it gives a satisfying run.  I guess it depends on what you want out of the engine.
   Type at you later,
  Dan McEntee

Rework can mean anything. If the tuner doesn't know the application you can run into some trouble. For me the expected result is to match the power level to the air frame and still get the type of engine run you want.

Most of the time rework means lowering the compression ratio and installing a PA NVA both of which reduce power a good bit as noted above.

I think the compression is just fine on the LA46 but the head is a raw casting. I just lightly skim it with a special form tool I made to smooth and polish the combustion chamber. Helps with fuel economy and no real loss of compression. 

LA46 is very tunable and can be made to produce more power with a couple of simple mods to the intake timing and piston skirt. If you're putting one on a Twister you can tune it for less power with venturi size.

You can use a metal backplate or use sealer on the factory backplate with flat washers under the bolts. The expected result there would be no air leaks. I like socket head cap screws but the JIX screws are good if you have the right driver.

Not much you really need to do with the LA46, it runs great right out of the box.

MM