How can i get more horsepower out of my factory 454 chevy big block engine?

get it bored out, get the heads ported and polished, different pistons, hot camshaft. Run a high rise intake manifold. Good carburetor. Good ignition system like msd,etc.

K &M filters, moroso ignition system, or you can get a chip to put in it too

Hands down, biggest bang for your buck – headers.

it really depends on what kind of 454 you have…. 1970 ls-6? 1990 454ss p/u? 1977 surburban? lots of variables….. but the one answer that is common to all is to increase the amount of air/fuel in , and increase the amount of exhaust coming out. Any engine is just a giant air pump- increase the amount of air going in and out, and you will make more hp.

port and polished heads, intake and exhaust, titanium crank, high profile cam/high compression, and to the extreme: supercharger or turbo.

The first things needed are a perf.air intake (preferably cold air), headers and a good dual exhaust with perf. mufflers. After that the skys (and your wallet) are the limits.