I've been doing some preliminary research on building a sb2.2 headed engine. I would go with a bigger cubic inch, though... probably a 427 using Dart Iron Eagle raised cam standard deck height block. While doing research on the sb2.2 heads, mostly the NASCAR take-offs that I would get worked over for drag racing, I cam across the GM Performance "146" splayed valve head. Does anyone have any experience with those? I never seem to see anyone talking about using them. Were they the original NHRA Pro Stock Truck heads? I can only find them for sale "semi-finished". Are most cylinder head porters able to finish them or have a CNC program for them? Just wondering what those with the knowledge thoughts are on these vs the sb2.2.