"The new pistons that Kanters and Egge offer, are they same as OE pistons? I have heard somewhere that they aren't the same and that they are lower compression ratio. If that's true,is Wiesco the only piston manufacturer that can make custom designed pistons for the MEl 430? Just considering all my options before I order an engine kit."
Yes and no. Most pistons I have seen are generic, i.e. they are not MEL specific (most are modified BUICK). One reader @ LCOC bought a set of 462 pistons from EGGE and the dome seemed correct. The MEL combustion chamber design is defined in the piston tops, unlike most other engine series. Without that special dome (do not confuse as a pop-up) the engine will merely be an air pump.
WISECO has a MEL freak working there that will help you along. There is another custom manufacturer, but I cannot remember the name.
http://www.thelincolnforum.net/phpbb3/viewtopic.php?f=1&t=24871&p=171897&hilit=mel+piston+design#p171897
http://www.thelincolnforum.net/phpbb3/viewtopic.php?f=1&t=25046&p=173171&hilit=mel+combustion+chamber#p173171
