New build A833 18 spline with Gear Vendors OD.

My 360 based W2 engine hit 8k in a blink with factory flywheel .
My new 408 W2 with only 246/250 duration not so fast even with a 20lb McCloud SFI steel flywheel .
I can understand that, a very good friend of mine ( who built my engine), has explained to me about an engines rate of acceleration, and how it relates to performance. This can't be accurately measured on a dyno, but becomes very evident at the track. Not surprising to hear your account of how a 3.58" stroke accelerates vs 4".