I have no experience with the EQ heads, only thing i can relate then to is the 340/360......so what i suggest may not work or may even be counterproductive.
I too have a (small) flow bench that has been calibrated.
I guess you are using a pilot probe in the intake to know that the air speed is high!
Are you at "400" fps, or, is it way over 400 fps (430-450)and is it one little point in the ssr or is the 400+ across the hole ssr(Short Side Radius)
As Brian has suggested, on another thread, install the manifold and see what happens.
With the intake manifold bolted on, the "High" speed my not be there.(aka not issue.)
I wouldn't worry about it falling off at .550' lift unless your plan's is a 600+lift cam..........Then you might be better off with a different head.
Looking down through the valve bowl area, does it have a small lip on each side of the ssr were it turns into the runner? If so rounding that MIGHT help slow the ssr speed down a little.............................