Yes yes yes!
If it's an OG '68 engine, it might have slightly higher compression. The later ones had piss weak compression, through a lower compression height on the pistons. (Most were 1.720 inches) which puts the slug quite far down the bore at tdc. If you pop off a rocker cover, there will be a casting number cast into the heads. The last three digits denotes which model heads they are. Theres a beaut how to thread in the small block forum at for A bodies only (it's a sticky thread) entitled "318 head porting for the average joe"
The guy there got his flowing enough air to support 410hp iirc. (I havent read it for a while)
Since you have nice headers, give the ports a tickle, fit a cam, (go for like a Comp XE262 or lunati voodoo equivalent, unless you wanna also fit a hi stall torque converter too)
A nice 4bbl manifold will also help. For a mild build I'd say an edelbrock performer, performer RPM, or if you can find one an Edelbrock LD4B/LD340. (Port matching would be required with the LD340)
Which your shifts, the fitment of a trans go TF2 shift kit is standard practise for the torqueflite. (I'd be curious as to if it's a 904, or if it got the heavier 727 cos it's such a big beast of a car?) As for your carb, a Holley 465 4bbl is a nice size for a mild build. I wouldnt go much over a 600 for a cruiser. People are shockers for over carbing their engines. A smaller carb has higher air speed through the venturis, which gives great bottom end throttle response. (I've got a 390 cfm on my 318, and it's super punchy down low)
Mopar or no car!