sheet metal or cast intake ?

528 Ahead deal
for truck pulling
i ran an old style single last few yrs
i got ahold of a newer ex514 intake that will work
i was gonna use that
but i get a sheet metal also
i run a single 1250 dom
i am wondering if the sheet metal deal would be bad for lower end
i like to com eout at around 3500-4000 rpm's
and spin it to 7000-8000 rpm's right away

I'd stick with the cast manifold. Properly port matched,it should be as good or maybe better than a sheetmetal deal, depending upon who is building the sheetmetal intake.