P/S cars are chromoly and now T/S cars are also and they will Cert. to 6.0
A 2X3 car hasn't ran in pro stock or top sportsman for years and a lot of those cars want cert. to 7.50 there are a lot more bars in critical ares that wasn't necessary when they were built .
The chassis rules have been updated a lot in the last few years if you need a car that will cert to 7.50 it would be a good ideal to take a chassis guy with you if it isn't already got a 7.50 cert. on it .
My nova was a 7.50 cert. car until this year and now it will only cert.8.50 unless i ad a funny car cage and a couple of other bars to it . but it will never see a 7.50 pass anyway it runs 8.70"s so the 8.50 cert. will be fine.