[JHS]

I do not profess to be an expert on the Impala but according to the research I have done the exhaust manifolds are stock w/correct casting numbers per Colvin's book and have been powder coated. Although the 3/8" fuel line may have been used on the 390 hp SS427 it also had a return fuel line; the L72 did not and my car does not. I did not look closely at he master cylinder though so you may be right.