The "W" motor was rated between 200 and 220 hp. The 220 was with the CPI system (What you call the spider) and the 200 was the TBI unit with 500cfm body. Cam specs are 277 int adv duration, 274 exh adv duration. Valve lift is .432" int, .440" exh. LSA @ 118. 050 duration for both int and exhaust are .208. It does run very well in this stock trim especially with the later model Vortec heads. Flow was improved slightly in these heads to give it a bit more umph.