I figured it out.  This afternoon, I built a valve spring compressor tool, 
and took apart my heads.  The valves didn't seem to seating properly, like 
the contact area with the seat was much too far toward the stem.  I couldn't 
figure out why until I noticed that the valves are oversized.  39/35.5 mm to 
be exact.  I just figured that the seats were not cut enough to get the 
valves to seat right and dismissed it.  Not so, the seats were _never_ 
replaced with oversized ones!  It looks like the valves in a stock 1600 head 
were just replaced with the larger valves.  So, what to do?  This is very 
low class work, and I still can't believe someone would do this.  

I would like advice from the list on this matter.  What should I do from a 
legal standpoint?  It is blatantly obvious that I was sold defective 
merchandise and I have all the proof to boot.  Should I just send them a 
nasty-gram, of what?

BTW- The place is called "Performance Specialties" aka "The Latest Rage."  I 
would advise that nobody do business with them.

Thanks all-