Beware that "Last Ounce" of speed.....You may not like it!

No matter how fast our cars are-gearheads are constantly looking for ways to go faster. On a race car this is a good thing, but on a car that your going to drive at all on the street, sometimes this can really bite you in the ass. Here's some good examples of this. # 1. A national magazine tested a bunch of intake manifolds on a small-block Chevy. The dyno test showed that the Edelbrock Performer RPM "Air Gap" model-with a raised plenum so air could flow under the carb-was worth 10-15 hp over the regular "RPM" which was already the top dog of street/strip intakes. This was great in sunny California. However, they recieved a flood of angry letters from readers in the midwest and Rocky mountain states saying that they bought these manifolds, and then experienced carburator icing which made their cars virtually impossible to start in cold weather, or if they would start, they wouldn't run properly for 15-20 minutes! These people said they were re-installing their old manifolds and gladly giving up that 10-15 hp in exchange for a car that would start reliably!!  # 2. "We shall Overcam."  Another magazine chronicled a camshaft test. Their test mule was a 383 Chevy stroker motor that was already pretty "built" the way it came. The cam in the engine idled at 800 rpm and had 14 inches of vacuum at idle. Perfect for a street machine. The "hotter" cam they installed made 28 more hp, and 24 lbs ft more of torque. However, it only made 9.5 inches of vacuum at idle, and wouldn't idle below 1100 rpm. It didn't have enough vacuum to operate the power brakes on the car it was in.  Again, the engine was already making 427 hp with the cam it came with, so making 455 wasn't worth the loss of idle quality or ability ro operate vacuum accessories!! # 3. High Perfromance Pontiac had a 79 Trans Am with a stompin' 455 in it. It ran 12.80's with a 2.56 axle ratio, and ran 12.40's with a 3.73. However gas mileage dropped from 16 mpg to 11 mpg, and highway cruising rpm went from 2300 to 3,000!. The owner felt that 4/10s at the drags wasn't worth the loss of drivability.  So be careful chasing that last ounce. Mastermind