There are for sure 2 things different, as david said funny car cage and the other is the addition of X bars on the chassis under the driver area, i don't know for sure but may have to have X side/door bars also. I have a rule book and it doesn't specially spell this out. I know 7.50 must conforn to SFI 25.2 but not sure what spec. 8.50 unless it's 25.3. Unfortunately you can't get those specs without buying them from the SFI web site. I have a B/P for a tube chassis 7.50 spec car, but not an 8.50 B/P
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