"Stealth" modifications that can make a stock-looking car scream......

Had a few people ask how they could have their musclecar look totally stock but be lightning fast. Here's some tips on how to do it. # 1. More cubes. The Saying-"There's no substitute for cubic inches,except cubic dollars" is still true. There are stroker crank kits available to turn a 350 Chevy into a 383,and Dart offers a short block thats 427 inches! There are also crank kits to turn a 302 Ford into a 347, a 351W into a 392 or a 427, a 360 Mopar into a 408, a 400 Mopar into a 451, and a 400 Pontiac into a 455 that are all reasonably priced. More expensive, but still doable-there are kits to turn a 454 Chevy into a 496, a 440 Mopar into a 505, and a 460 Ford into a 514. # 2. More cam. No one can tell what cam is in your engine. Just don't go overboard especially on cars with automatic transmissions. Sticks can tolerate wilder cams better because idle quality isn't as important and the driver can launch at any rpm he wants by manipulating the clutch. The cam manufacturers usually give you good advice-i.e.-"Needs at least 3.55 gears" or "Needs at least 2,000 rpm torque converter". Another way is higher-ratio rocker arms to boost lift. Most cars have 1.5 ratio rocker arms. Switching to 1.6 or 1.65 rockers can give you a 10 percent boost in valve lift. In other words-if your cam has .450 lift with 1.5 rockers 1.65s will give you .495. # 3. Mechanical advantage. Swapping your 2.56:1 or 2.73:1 gears for something in the 3.23-3.73 range will give you a stunning improvement in 0-60 and 1/4 mile acceleration without hurting freeway cruising rpm or gas mileage too much. If you have a car with an automatic transmission a converter with a little more stall speed can give you a big boost as well. But be careful-especially with big-block cars-sometimes the extra stall speed can actually slow you down by blowing the tires away-too much wheelspin. # 4. Exhaust. Even if your running stock exhaust manifolds-they can be ported and extrude-honed, and 2 1/2 or 3" inch pipes, a balance tube or an "X" pipe and low-restriction mufflers can free up as much as 30-40 hp. # 5. Induction. There's lots of room for improvement here and you can still look stock. For example-the Carter AVS carb used on Mopar 383 and 440 4bbl engines only flows about 585 cfm. Edelbrock makes an 800 cfm AVS carb that would allow these big-blocks to breathe properly and pick up probably 20 hp by going to the larger carb. If your pre-1967 GM car has a Carter AFB on it-they only flowed about 500 cfm. The Edelbrock Performer series is an exact copy of the AFB and is available in 750 and 800 cfm versions. This works on Dual-Quad applications as well. Especially if you've gotten more cubes and more cam, and maybe more converter-you can use more carb. Swap the 625cfm AFBs on your 421 Pontiac, 409 Chevy or 426 Hemi for 750 Edelbrocks. If you remove the little "Edelbrock" emblem off the front no one will know the difference. On later models-Jet and other companies offer custom-jetted 750 and 800cfm Quadrajets for GM cars. For '70's 440 Mopars Summitt Racing is selling remanufactured 800 and 1000cfm Carter Thermo-Quads. On some models you can change manifolds. GM Performance parts offers an exact replica of the Z/28 / LT1 SBC manifold in cast-iron. Pontiacs from 75-79 have the EGR valve intruding into the throttle area which really limits power above 4,000 rpm. By switching to the '67-74 manifold your 400 or 455 will pull hard to 5,500 rpm instead of starting to wheeze at 4,500. # 6. Ignition. The '72 and later Chrysler Electronic distributor uses the same cap and looks the same externally as an earlier point type. On GM and Ford applications Petronix offers an electronic conversion that will fit under a point-type cap. You can hide an MSD or Jacobs box in the glove box or somewhere under the hood. You can paint a Hi-Performance MSD or Mallory coil black and make it look stock. Switching to electronic ignition will give you better cold starting, better gas mileage, and better high rpm performance, since most points "sign off" about 5,000 rpm. You can play with plug gap as well. My 403 Olds Trans-Am, even with headers and real dual exhausts and a single-plane Holley Street Dominator intake wouldn't rev past 4,700 rpm when I first got it. I called Mondello Performance ( THE Olds performance Gurus ) and they said to switch the R46SZ plugs ( an .080 gap ) for some R45S plugs. ( a .040 gap. ) This single change allowed it to pull hard to 5,400 rpm!!. It picked up 700 rpm on the top end even with the lazy stock cam-simply because even the mighty HEI couldn't fire an .080 gap at high rpm. Hope these tips help. Mastermind