You shouldn't be too impressed or confused by the Super Chevy show cars, most of them are as you said running B/BLK chevy engines and are paid in by super chevy, Most of them are running less than 50% nitro to keep the maintenance down on the motor. True they are crown pleasers, but would be nowhere near competative on the NHRA or IHRA tour. that et and speed translates to a 6. second run it the 1/4 mile on the tour nitro funny and dragsters run 3.00 to 3.20 @ 250/280 in the 1/8 mile. They are what they are and that's show cars for the crowd. Over here at Baton Rouge super chevy a few weeks ago, there were 2 local promod cars running 3.80's and 3.90's, one of them a Hearst with a carbon fiber body, but both had Hemi's.
Zip.