A cooling system consists of: The radiator, radiator cap, overflow tank, water pump, thermostat, fan assembly, fan shroud, hoses and the coolant. (The water passages inside the engine block technically are part of the system, but other than cleaning them during an engine overhaul, there is no practical method of changing their operation.) Read more

The most significant advantage of tube headers (with a common collector) is their ability to lower the atmospheric pressure within the collector. This provides scavenging of the combustion chamber, which more effectively removes the exhaust gases and tends to “suck” the intake charge into the chamber during overlap. The effectiveness of the scavenging is dependent on proper matching (tuning) of the header pipe sizes to the engine RPM and application. Read more

All rear drive cars have a differential assembly to allow the drive wheels to turn at different speeds when necessary. When turning a corner, the outside wheel speeds up while the inside wheel slows down. Although this allows smooth turning, it presents a problem if one of the wheels is on a slick surface. The wheel on the slick spot spins while the other slows or stops altogether. The result is no movement of the vehicle. In about 1957, the auto designers incorporated two clutch-like devices into the rear axle assembly (one on each axle) as an option. It was called a “limited slip differential”. Of course, the advertising people had to get some mileage out of this new development so they came up with unique names for each Make. Chevy was called Posi-Trac, Pontiac was Safe-T-Track, MOPAR was Sure-Grip, Ford was Equal-Lock, etc., but they are all limited slip differentials and they all function similarly. Read more

“Pontiac Intake Manifold Tests on a well tuned stock type 455 in a 3900# vehicle.”

Note; The following summary of intake manifold tests was prepared prior to the formal article in “High Performance Pontiac” magazine published several years ago.

After testing six different manifolds, I have began to understand the Aftermarket’s definition of “High Performance”. It generally means a series of engine modifications that allows/causes the engine to run at much higher RPM. It does not necessarily mean increased performance. Read more