No, not the Great White Whale, how about an iron Bullet decompressor retro-fitted to a 500 AVL head? Not possible, so it had to be done.
Pictures first:
URL=http://imageshack.us/photo/my-images/209/dcv3.jpg/]
[/URL]
URL=http://imageshack.us/photo/my-images/836/dcv4.jpg/]
[/URL]
Basically you drill and tap for a 14x1.25mm spark plug thread opposite the existing spark plug. Some of the finning between the rocker boxes has to go, but with a milling machine and some careful work (rather than my butchery of an innocent component) you could sacrifice a lot less. I am informed by a UK Bullet specialist that subsequent overheating should not be a problem here in NW Europe as the sheer size of the rocker boxes mean they conduct enough heat away already, not so sure if that holds good for the Southern States of the USA or India, though!
More details if anyone is interested.
Regards,
Adrian