CHEAP? Index the plugs. (gap facing the valves). This promotes more efficient flame propagation across the face of the piston. cost:(Free) BASIC after market H.E. ignition system with proper plug wires. cost (under $200..... remember I said BASIC) MAKE SURE the carb. CFM is LESS than or EQUAL to your best guess of what the intake and heads are flowing. Double pumpers might be "cool", mechanical secondaries might sound "cool". At the very least vacuum secondaries won't open till enough mass air flow is moving thrugh to open them. Dump all that air and fuel in one shot and she'll nose dive every time. Small blocks make 800 plus with a 490CFM. cost ( under $100 for a used 500CFM carb) High flow air filter (cost under $50) Set the timing correctly. cost (free) Plug all vacuum leaks. cost (almost free) BIG open flow muffler cost ( under $100 if you do it) Cut the belt to AC if it doesn't work. cost (free) All these things cost less than $500. I don't know what H.P. or torque numbers you have. I'm guessing a "smogged" 454 probably makes around 225 HP. The techniques described will add 2-3% each if they are applied. You may have already done some of these things. But... you can probably pick up 30-35 HP if all these are applied. The bigger HP will cost you considerably more money and will not fit the category of "cheap". Good luck.

Sources: Basic physics E=MCsquared, Force=Mass x Acceleration, Boyles Law, Charles' Law Force= 700 C.I. x (2 x 50,000 volts) x B.D.S. x CH3 NO2 x 6 stage high gear x 4.5 G's / 1320 ft.

If you can find some older396 bathtub chamber heads,and a stock chevy 375 H.P. solid lifter cam,good intake and headers ,you will wake that car up for under a grand.