Sell the Stealths and step up to a max wedge port size or bigger
My old pump gas Duster ran high 10.60s with ported big valve 906, ran 10.30 with CNC ported eddy RPM and ran 9.993 with a set of Indy SR M.W. size intake ports non CNC ported
I did dyno test a set of CNC ported 440-1 on that motor and they where 50 HP better than the SR M.W. heads, I put the ported 440-1 on my bracket race 526 C.I. high deck 440 motor to sell it
Bottom line is more air, more fuel, more power