Is it a Weiand two piece SS intake manifold for stock 440 intake port size? If so the head ports will limit the power, sorry
if you wanted to go to a Max Wedge port size and weld up the intake to head mating surface and then enlarge those ports to match the head ports it would make more power than it will with the stock 440 port sizes
I have owned and race Mopar six pack motors for more than a little while, with both stock intakes and after market intakes, the more air and fuel you can get to go through the motor the more power and torque you will make
On your deal I would look for some 270 CC version Trick flow heads or a set of Indy SR M.W. port size or set of Indy 440-1 heads for max power and have your intake work on, welded up, to match the heads, big lift solid roller cam with a lot of lift and duration around 255 to 270 @.050 on both lobes with a LSA of 104 to 108 and install the intake lobe center between 3 to 6 degrees advanced, closer to TDC
My last pump gas street motor (517 C.I, 4.375 bore, 4.300 stroke,) I built made over 700 HP with a Eddy aluminum low deck six pack intake with a set of slightly modified 1970 Holley 440 six pack carbs on Oregon 92 octane pump swill. It was in a 1971 Duster that weighed right at 3450 Lbs. with me in it, best et through the mufflers with the air cleaner on using a set of CNC ported Eddy RPM 440 size intake ports was 10.39 at 127.+ MPH
I swap the heads , intake and carb later that winter to a set of Indy SR M.W. size intake ports and a Indy 400-3 intake manifold with a stock Holley #9375 1050 CFM non HP Dominator, that made the car run 9.993 at 134.+ MPH at the same track the next year in very similar weather with less than 50 FT. difference in density altitude, the track wanted to throw me out after that run due to the car and me not being NHRA certified to run quicker than 9.999 ET
I told them I would slow it down by staging a little deeper and short shifting it, which I did
Have fun, build it correctly once
Don't do it my way, three difference times