No Replacement For Displacement
Q: How can I upgrade the horsepower of my '03 Silverado 1500 4.8L more than the K&N, throttle body extender, powerchip programmer, and Borla exhaust already on the truck? I know the next step is probably some headers, but what else can I do on a budget? Thanks in advance.
A: As stated in the title, you need some inches. The little 4.8L trying to pull around your '03 Silverado is dying! Adding headers to your small 4.8L engine isn't going to give you as much torque increase as you need to move your truck. We're now about 10 years past the release of the 6.0L truck engine. You can pick up LQ4s and H.O. LQ9s at wrecking yards around the country and drop one in for a little excitement. This would be the most affordable upgrade to give your truck a really noticeable increase. You've added most of the standard bolt-ons. You could add a supercharger, but it would cost more than a used 6.0L engine by a long shot. Also, you could have the swap done in a single weekend.
Check out what's available, and maybe you could find an affordable LQ9. These engines had the highest power rating: 345 hp from the factory. Then you would really have something to build from.
Technical questions for Kevin McClelland can be sent to him at firstname.lastname@example.org.