remember making more power also requires better more expensive parts. The most power for the least money has issues,,reliability and or drive ability.some compromises are acceptable or forced. decide what product you need"THEN" decide the route to take.
IE: a 454 makes good power reasonable price,but is tough to stuff in an old chevy2 or old vette.In a pick up a 454 is a great idea,,,
an LS motor or similar newer technology is a great upgrade over the old carbed cars but cost more,,, what do you need? what is the priority?