Optimum Exhaust Pipe Diameter (inches)
Flywheel
Horsepower		Single	Dual		Single System
150		2
175		2 1/8			Optimum Pipe Diameter (inches)
200		2 1/4			= sq. rt. (flywheel horsepower/40)
225		2 3/8
250		2 1/2			Dual System
275		2 5/8
300		2 3/4	2		Optimum Pipe Diameter (inches)
350		3	2 1/8		= sq. rt. (flywheel horsepower/80)
400		3 1/4	2 1/4
450		3 1/2	2 3/8
500		3 1/2	2 1/2		If optimum pipe size is not available,
550		3 3/4	2 5/8		go for the next biggest pipe size
600		4	2 3/4
650		4	2 7/8
700			3
800			3 1/4
900			3 1/2
1000			3 1/2