Electric cooling fans, like this one from Flex-A-Lite, use virtually no engine power except for the mild electrical load at the alternator, which really cannot be measured. These work off a thermostat that turns them on when coolant temperature in the radiator reaches a specific temperature.
Cooling Fan
For as long as there have been Ford hot rods, there has been speculation over what type of radiator cooling fan to use. These days, you have a lot to choose from. Flex-A-Lite flex-fans flatten out and take less power to turn at high revs. They are quiet, moving large quantities of air with less noise.
There are also electric cooling fans that consume virtually no engine power and do a pretty good job of cooling, depending on the fan you choose. Always err on the side of overkill and opt for a greater capacity than you think you will need. Electric fans require a subelectrical system consisting of a fuse or circuit breaker and a relay for proper operation. They should operate only when the ignition is turned on.
The most efficient engine-driven radiator-cooling fan isn't a flex-fan or one of those six-bladed steel jobs--it's the thermostatic clutch fan that engages only when needed. The clutch fan uses the least amount of engine power because it comes online only when it is needed.
Flex-A-Lite fans are available in a variety of colors and sizes, plus reverse rotation for the 5.0 crowd. | 
The most efficient engine-driven cooling fan is the thermostatic clutch fan. Do not get this confused with a plain old-fashioned clutch fan. You want a thermostatic clutch fan that engages based on radiator coolant temperature... | 
...When the coolant is hot, it engages. When the coolant isn't hot, the fan free-wheels at a much slower speed than the water pump pulley. |
Squeeze Box
If you are looking for quick, bolt-on power, nothing quite does it like nitrous oxide injection. Nitrous-oxide gas works hand-in-hand with the air/fuel mixture in your engine's combustion chamber to make from 50 to 150 instant horsepower. Although this is a terrific idea (used as far back as World War II in fighter planes to help make more power), it doesn't come without a price. When you use nitrous, you are changing the way fuel ignites in your engine's combustion chambers. Too much nitrous and not enough fuel can and will cost you an engine due to extremes of chamber heat. This is where you have to temper your ego and watch how much nitrous you inject into your engine's combustion chambers. To get there safely, you have to determine proper carburetor jetting, fuel pressure and volume, spark timing, and more.
The Smoothest Path
One of the most common engine compartment shortcomings is the sloppy routing of ignition wires. Poorly routed ignition wires can cause crossfire and misfire, contributing to poor performance. Not only that, they look awful.
Made For You has quick answers for ignition wiring woes. Check out this Engine Wire Loom kit being installed by Mark Jeffrey of Trans Am Racing on Carroll Shelby's 427W stroker. These Made For You kits, as their name implies, make the task of ignition wire routing easy. What's more, they look terrific.
Sequential Turn Signals
Scott Drake Reproductions introduced sequential turn signals for '65-'73 Mustangs last year, and they have caught on like wildfire. This is an affordable, easy-to-install restomod item that can change the personality of your classic Mustang for the better. When you signal, it catches the people behind you by surprise. See Virginia Classic Mustang for this and other great restomod ideas from Scott Drake Reproductions.