
Originally Posted by
blueguy
Hell froze over...
Because this is correct.
If your stock L67 car makes 200WHP or more, you'll be lucky.
Adding headers lowers boost numbers because the car is flowing more freely...you then add the pulley to make up for the loss, because all it is doing is shifting the power up...you're not losing ANY power, and it's easier to launch because the torque is now geared a little higher in the band.
HiPo Pontiac did a test I think on an SSEi back in the day, and it gained close to 30WTQ and north of 20WHP. L36 gains were close as well...because I think they tested a GP GT too, just to compare...and to show how crappy and restrictive the manifolds to the catback really are.