[Stan Weiss]

Originally Posted by BruceWilkie

Stan as the stroke gets longer, the valve lift rate "wants" to be greater due to piston speed. Two motors same displacement with heads of same flow capabilities but different bore and stroke... the longer stroke motor isnt likely to acheive as high a VE as the shorter stroke motor... it certainly WONT if you use the same cam and rocker ratio... and making rod length ratio equal or different wont make much if any difference.

Keep in mind bigger bore motor could run bigger valves and be made to flow more than the smaller bore could... again same displacement, the bigger bore motor now has the potential for even greater VE.

VE is king in making power per cubic inch.

Bruce,
There are a few sub threads going on here. With the 572 I was talking to Curt about large ci engine for bracket racing.

For the 2.3 thread 575 * 2.3 = 1322.5 HP

Bore = 4.375 - Stroke = 4.75 - Rod Length = 6.7 - RPM = 8400
Piston Speed is 110.83333 Feet per Second
Piston Speed is 6650.00000 Feet per Minute
Maximum Piston Velocity 11090.732 FPM @ 72.362 Degrees

Bore = 4.44 - Stroke = 4.03 - Rod Length = 6.7 - RPM = 9600
Piston Speed is 107.46667 Feet per Second
Piston Speed is 6448.00000 Feet per Minute
Maximum Piston Velocity 10579.730 FPM @ 74.498 Degrees

Because of the difference in RPM, there is not that great a difference in piston speed.

VE is king up to the point it is maxed out then the only way to increase HP is to add cycles (RPM)

Stan