My mild steel Daytona already had an 8.50 cert and a funny car cage. I paid to have it upgraded to a 7.50 cert and was told it needed four bars. The guy doing the work had it up on his hoist and an NHRA certification guy found 3-4 more bars that needed changed out because of rule changes which was fine with me. My blue heads up car is chrome moly and has a 6.50 NHRA certification