I'm installing a new 383 and wanted long tube headers...it says "Must modify lower A-Arm support bracket on 1979-81 models"...
Can someone tell me what that's about...thanks

 

I have a 1979 Z-28 RS with a supercharged 377 cubic inch small block Chevy ,With Doug Thorley big long tube headers with both stock and tubular "A" arms..And I never had to had to modify my "A" arm bracket .I have had a number of different small blocks .brand of headers with no issues,It depends on what brand of headers you have otherwise.unless you have an exotic cylinders heads you shouldnt need to