Where drivability (I define as off idle to <WOT) throttle torque is important (and for most dual purpose cars it's way more important than most will admit) having a slightly undersized higher velocity port will be more responsive and fun to drive. At the track and with the optimal gearing (critically important) a larger port will et quicker, though driving it around on the street it will feel more sluggish or will be far more dependent on stall/flash....which means pretty inefficient if only in terms of how it's mainly going to be used.

Brad do you have Steve Dulcich's hp/tq graph from his 2003 EM 470/Chapman or our own EM Stage VI high velocity/epoxied MW entry? I don't think those had much if/any perceivable dip, but 470's hit a little quicker and harder on a dyno than a 440 of the same peak power. I think a big part of the strategy for EM is the fixed rate of acceleration in 100R's/sec against WOT standardized testing. I think guys like Kaase and Bischoff figured out very early that tight lobe centers combined with early ICL's get the motors a harder dyno "hit" and perhaps help the combo carry momentum...like 'pedaling downhill' of sorts. in other words the gains in torque below the peak more than offset perhaps losing a couple up top, the motors are obviously much more "lift dependant" from peak torque to peak power because the durations have to be kept relatively short to achieve mid range velocity at the slower RPM/piston speeds.

On the street or at the strip with a high stall converter or a clutch that 3500-4000 won't have much bearing with the right converter, but velocity has a TON to do with responsiveness. My approach has always been on a big 500" motor it shouldn't need to be so converter dependent to get to the sweet spot, so I'm a huge fan of velocity. But of course my philosophy for dual purpose cars is more likened to a road-race shortblock with killer heads for the best (or near best) of both worlds. My 517 Chapman design was based a lot on what I learned from Steve's 470 motor and discussions with Dwayne and Dan Costello....and it's the flattest/broadest torque and fastest revving wedge I've ever built...by a mile.

Last edited by Streetwize; 12/11/17 11:52 PM.

WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0