camshaft and compression ratio
StrokerScamp is 'right-on'
If you believe engine simulation programs like desk top dyno,, I can show that for improved torque and Hp up to 4000 rpm, changing cams is the last thing you do,, start with improved carburation and exhaust, raise compression, optimize timing, head porting and OS valves, then change the cam...
most folks do the above and change the cam at the same time, because they are already into the motor. Its the "package" that makes the difference,, and the package is determined by your goals and available $