When we first started there were no block-hugger headers for an LS1. It was still kind of a new crate engine. We attempted to use a pair of stock cast manifolds for an '03-'06 GM truck (bottom). We even tried to modify them to fit the Bruiser chassis with no success. We then went on to modify a set of JBA headers for the same model truck (PN 1850, middle). The idea was we could cut them up and weld on them without the cracking that the cast manifolds would get. Still no luck. So we put the exhaust on the back burner until two years later when Hooker began offering polished stainless steel LS1 block-hugger headers (PN 2314HKR, top).