The NMCA uses NHRA rules for Stock/SS and shootout cars. Which is why Holley recognizes this as the first 7 second run by a shootout car. AS for the aluminum block I am sure it is all about the weight. They do have minimum weights but being able to put that weight were it is needed or will work best is likely the reasoning. Car was built by MR2 and I'm sure that's the thinking. The Air was KILLER when they made that run, like unheard of for Florida. Water grains below 20 the barometer was 30.+ and the DA was in the 500' area. Before the rains came Saturday