the Hemi has new pistons (10.5 vs 9.4 compression), rings, and camshaft. The cam, a small step above the factory '70-'71 grind, briefly ran in my green Duster 20 years ago. With the Hemi spending time on the engine dyno this January getting sorted out, I'm hoping it is a set the idle and done.... start up.
the biggest difference is a swap to the latest generation K with the Hemi positioned slightly to the right and slightly higher (appox 1/8" either way) and of course several tweeks, like spacing the clutch arm for better throw and rod alignment....ya know, hot rod 101....when apart, make it better.
also added the 12" QA1 coil over (#DS-501) with 12" / 350 lb springs VS the 10" with 10" /400lb spings. The Duster sits the same as before....ride height on the shock is right on spec (13-7/8") with the coil at 9.25" at ride height....right where QA1 suggests (25% to 30% of full length of the 12" coil spring). I have 1.5" of pre-load on all four corners and the Duster sits level in the front and appox 1/8" higher on the left rear vs right rear (driver weight allowance). I switched out the front anti-sway bar from a 1-1/16" to a 7/8". The whole combo makes for a smoother ride to the coffee shop.
I love hot roddin!