Jerry, No way partner do I take your contribution to this topic as any thing other than trying to get to the bottom of this issue.
I am fairly short on facts on this matter.....you know all about the famed post card & the sum of my info...
Okay, so it's not an accurate statement that at some point in our rpm band that the by-pass excludes the rad core? I got that impression from THOTB where they talked about the prep for the car & the throttle stop & rear gear, etc yielding a cruising speed below a certain rpm to avoid the by-pass, >5600 rpms is my recollection?
I do know that I saw a thread over at CF where one of the aftermarket makers freely admitted that our gpm flow ( which he thought to be excessively high ) could cause a ballooning of the tubes if left unrestricted because it was so far & away beyond any common domestic water pump's gpm flow.
Tyler had a solution ( proly the same as yours & LPE's ) where he used a restriction in the by-pass outlet of the housing, a cut spring stat I think with holes drilled like yours, and one of the really high end aftermarket radiators. If I understood correctly this all yielded less by-pass or moved the by-pass up in the rpm range.....
..I don't remember which....so you could get flow thru the rad at high rpms like during an open road race situation. I would figure in an ORR you're spending a great deal of time above 5k rpms?... not me
but a good driver would be, no?
Next year at the Gathering I'm going to ask to have this whole thing explained if we have a seminar where Marc or Mr. McLellan is available to lend their knowledge.
My simple answer is to keep the by-pass as is, redesign the impeller to lower the flow rate......(Yea, right, simple!...ignorance is bliss sometimes
).... and use a high end radiator.
Tom