My GF's Duster 360 is slow as hell !!!

hi guys !! how it can be... i took my gfriends 76 duster and was it was boring as hell .. it cruise good but i mean for pedal to the metal power you feel no torque nothing...it kicks down like a 225 do you see what i mean , you dont go back into your seats ..it as a 3:21 open differential and her tranny is stock ...does she really needs a stall and more gears ????


- 1979 ..360-4 BBL -
-:now 365 cubic inch - 0.30 oversized
-TRW forged pistons
-Chrysler hi-perf rods
-chrysler purple camshaft .474'lift & duration .280
-intake holley dual plane ported
- 340 *J casting heads / valve 2.02/1.60
-shaved head for more compression now 10:1
-carburator edelbrock 625 cfm vaccum
-DOUBLE EXHAUST 2.5 inch
- HI-PERF DYNOMAX ULTRA-FLOW MUFFLERS
-spark plugs : ngk platinum
-taylor 8.8 mm
-high volume fuel pump holley
-high volume oil pump
-frame connectors
-mopar performance valve covers
-gauges autometer temperature/volts/oil
-radiator 4 core
-mini-starter hi-torq mopar performance
- cragars centerline
15x 3 1/2
15x 8.5

Must be the Holley Dual Plane Intake...

So with 3.21 gears and stock converter....what do you expect?

How tall are the tires?