Question: 99 trans am ls1 horsepower?
Answer: By 1998 the LS1 was under the hood of every Trans Am and Formula, rated 305 hp at 5200 rpm and 335 lb-ft of torque at 4400 rpm. The WS6 package cranked that up to 320 hp and 345 lb-ft, and in 2001 both versions got a 5-hp and torque bump thanks to a new camshaft and the LS6 intake from the Z06 Corvette.