Some "Stealth" modifications that can make big performance gains...

A lot of people ask me how they can keep their musclecar stock looking but still really run. There's several things you can do that will net big performance gains that no one can see.  # 1. Ignition. Petronix and other companies offer electronic ignition conversions that fit under a points-type cap. You can also hide an MSD,Mallory or Jacobs box in the glove box or other places.  # 2. Gears make it go! Especially on mid-70's cars switching from a 2.56:1 or 2.80:1 axle ratio to something in the 3.23:1-3.73:1 range can cut as much as a full second off your 0-60 and 1/4 mile times without hurting gas mileage or drivability too much.  # 3. Higher Stall-speed torque converter / shift improver kit. When they introduced the Torqueflite in 1962 Chrysler found a great performance boost not in the engine, but the transmission. It took GM and Ford years to catch up. Anyhow-swapping a stock converter ( most have 1,200-1,700 rpm stall speeds ) for one with a 2,000-2,500 rpm stall speed will give you a huge boost in off-the-line acceleration without hurting drivability. Don't go overboard-one with 3,000 rpm or more stall speed won't really work well with a basically stock engine-( on big-block cars with street tires you may actually go slower because of excessive wheelspin ) and unless you have 3.90:1 or stiffer gears your 60 mph cruise rpm will be less than the converter's stall speed which will cause the trans to overheat and maybe burn up. So err on the side of caution when picking a converter-but the right one can really help you launch like a rocket. B&M and TransGo offer shift improver kits that really firm up full-throttle shifts without being too harsh at part-throttle. # 4. Camshaft. A hotter cam can make a huge difference in a car's performance, and except for maybe a nasty idle-no one knows your not running a stock cam. Be careful not to go overboard in cars with automatic transmissions. ( Sticks can tolerate more "cam" as idle speed isn't as important, and the driver can launch at any rpm he wants by manipulating the clutch ). Bigger engines can tolerate more cam without ill effects-a Factory RAIV cam-for example would kill a 350 Pontiac, but would work fine in a 400 with a 4-speed and 3.42:1 or stiffer gears,and would be really sweet in a 455 even with an automatic. Read the cam makers recommendations-their catalogs will tell you-works well with stock converter, needs at least 3.55 gears, etc, etc. # 5. More cubes. This is kind of a deal-breaker for some people as they may not want to modify a numbers-matching engine. The solution is to put the numbers-matching one in the garage and buy or build another one. GMPP, Mopar Performance, and Ford SVT all offer mega-inch high performance crate motors. If you can afford one they are a great way to go. Even if you have to build up an engine from a junkyard core-no one can tell a 396 Chevy from a 454 or a 400 Pontiac from a 455 just by looking at it. And there are stroker crank kits to turn a 302 Ford into a 347, a 350 Chevy into a 383, a 360 Mopar into a 408 and dozens of other combinations I can't name off the top of my head. All other things being equal a bigger engine will always make more horsepower and torque than a smaller one. Anyhow-these "hidden" mods can offer a big boost in performance to an otherwise stock-looking car. Mastermind