Differences in stock exhaust manifolds?
I know the y pipes are different in that the catalistic converers on the newer ones have bolt on catalystic converters seperate before the Y pipe and the 98's 1 of the converters is made into it (Y pipe) and on my 98 SS the manifolds I see alot of the turbo guys run them and they are made alot like a shorty header which I would think flow better but not for sure on the flow.
the 99 ones are the log type and have more resistance. 01+ they made it out of cast iron and made it more free flowing due to the smaller cam. but the 98-99 had stainless steel manifolds
