Right, not with the stock valve diameter. The only reasons to keep the stock valve diameter would be if you had to run the 675 on a 273 or you couldn't afford larger valves. Both very good reasons by the way.
I remember telling somebody about 250-270cfm out of a 675, they just laughed...:happy1:
That short turn with the mondo valve diameter will damn near blend/lay back to the push rod pinch with the way the floor is....and that roof is mighty thick too ;)