About 10-15 horsepower is a noticeable change. Kind of like turning the AC off and on. You can feel the change in power. A spacer on this engine will net you a small percentage of maybe 1hp. We are talking fractional You will not ever feel, notice or have a use for the difference it will make. Complete waste of money.
270 horsepower 300 with flowmaster duel exhaust, kn cold air intake, and skunk2 cams.
I believe it is 260 horsepower.
The horsepower of a GMC Sierra is 355 hp.
vortec 454,1996 thru 1999-->>>290HP 410TQ
197 rwh stock
About 190 H.P.
215@2800. Rpm
397 hp
To be sure you need to tested on a DYNO.
The 8.1L vortec comes stock with 330 hp and about 450 pound feet of torque.
The Vortec 5.3 Liter V8 engine produces 295 horse power.
145.