NHRA Top Fuel uses a Hemi?

You think every top alcohol dragster..and alcohol funny car wants to throw away their current inventory of blocks..heads and cranks...and buy something new....

that is why nhra said no.. COST

same reason for the spec engine for fuel classes....they are lucky these days to get 16 top fuel and funny cars to show up...with only about half that many having a real chance to win.