1968 the RR Engine 383/335hp camshaft
(HP 383/335HP & 440/375HP, 1968-70 same cam)
IIRC off the top of my head cam spec.s if acually what was used
Hydraulic flat tappet, M/P 264* dur./0.464" intake & 268*dur./0.468" exhaust Gvl
The camshaft should have a slight/choppiness
bucket tee-bucket tee-bucket tee-bucket tee, a lil' rumble to it,
with the factory HP 68-70 Manifolds & the OE 2-1/4" w/h-pipe & dual exhaust
thru Hemi turbo muffs, w/tailpipes out the back
those pistons/with big valve reliefs, don't look like 'stock spec' either
While you're at it, a nice set of 1.6:1 Crane or Isky ductile iron adj. rockers,
along with the appr. style/length ball & cup style pushrods
it'd be like 0.510"in/0.514"ex GVL, using the same camshaft
it'd add a lil' % of duration too, keep the valves open a lil' longer
to sound meaner too
vs the factory 'not so accurate' mass-produced anywhere between 1.48:1-1.5:1 ratios
stamped steel, non-adjustable factory rockers
It would wake it up a bit, and sound a lil' better/meaner too
good luck