Motorcycle Repair: 883 to 1200 conversion problem, adjustable pushrods, stock harley

Question
I just installed the Wiseco 1200 upgrade kit on my sporty, and it pings terribly.  The kit claims that it doesn't require headwork, and the bike seems to have tons of power, but of course I don't want to run it any more until I figure out this pinging.  I wasn't able to use the gaskets that came with the kit as they were too wide and used stock Harley gaskets.  Also I used the 883 heads to get a bit extra on my low end.  Any suggestions?  Do I need a thicker head gasket for more clearance, or maybe adjustable pushrods?

Answer
As I stated I only know about ironhead sportsters, ones made between 1957 and 1985, But If I were you I would slow down the advance curve but if you have the stock ignition you wouldn't be able to achieve this so you will need to install an aftermarket system that has adjustable pots on it so that the curve can be adjusted. Hope this helps you out.