[Jorgeman]

Rich--would you characterize the miss as random or occuring at a timed frequency like it would if it was in a specific cylinder? Since you've done an excellent job of already replacing most normal ignition potential problems, I was thinking of maybe a sticking valve. The problem is heat oriented--which causes expansion--which might be pinching a valve and slowing or stopping it's closing and sealing. Any different sound at the exhaust when it's missing?
How hot is the engine after 40-45 mins? Which mark on the temp guage?
IF the problem IS a valve, you should be able to narrow it down by removing each ignition wire and looking for the one that DOESN'T change the miss pattern. You'll get some other ideas from this board also--these guys are great!

George 86T