SOME DIFFERENCES BETWEEN
CUP, NATIONWIDE and TRUCK series vehicles
updated 2-15-2008
Currently, the three top series -- Sprint Cup, Nationwide and Craftsman Truck -- run a 12:1 compression ratio. That rule went into effect during the 2001 season. They all use cast-iron, 5.7-liter V8 engines with aluminum cylinder heads, and each engine has a maximum displacement of 358 cubic inches.

But the main difference among the Cup, Nationwide and truck engines is the size of the carburetors -- 830 cubic feet per minute (cfm) in Cup and 390 cfm for Nationwide and trucks -- which allows a richer air-fuel mixture in Nextel Cup. According to the NASCAR media guide, the torque is 550 feet per pound at 7,500 RPM for Cup, 535 feet per pound at 6,500 RPM for Nationwide and 535 feet per pound at 6,500 RPM for trucks. That gives the engines the ability to produce horsepower in the range of 850 at 9,000 RPM for Cup, 750 at 8,400 RPM for Nationwide and 750 at 8,400 RPM for trucks.

This table is incomplete, as I find more info, I will fill it in, thanks

Stat Sprint Cup [COT] Old Car Nextel Cup Nationwide Truck
Engine Cast Iron 5.7L V-8
Aluminum Cylinder Heads		 Cast Iron 5.7L V-8
Aluminum Cylinder Heads		 Cast Iron 5.7L V-8
Aluminum Cylinder Heads		 Cast Iron 5.7L V-8
Aluminum Cylinder Heads
Displacement 358ci 358ci 358ci 358ci
Compression Ratio 12:1 12:1 12:1 12:1
Horsepower
(approx)		 850@9000PRM 850@9000PRM 750@8400PRM 750@8400PRM
Torque 550 ft/lb @ 7500 RPM 550 ft/lb @ 7500 RPM 535 ft/lb @ 6500 RPM 535 ft/lb @ 6500 RPM
Carburetor 830cfm 830cfm 390cfm 830cfm
Weight 3450lbs 3400lbs 3400lbs 3400lbs
Fuel Tank 17.75 gallons x 17.75 gallons 17.75 gallons
Wheelbase 110" 110" 105" 112"
Height 53.5" (min) 51" (min) 50.5" (min) 59" (min)
Length 198.5" 200.7" 200.7" 206"
Width 74.0" 72.5" 74.5" 75.0"
Gear Ratio 2.90 to 6.50:1 2.90 to 6.50:1 2.90 to 6.33:1 2.90 to 6.50:1
Spolier Wing NASCAR Supplied
was 55" wide x 4.5" high		 57" wide x 5.75" high 66.75" wide x 8" high
Front Air Dam
Splitter		 4.5" max x 4" min 7.5" min


This info is unofficial and compiled from sources on the internet, books and magazines.

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