Small Hughes cam in 318

I've never tried them but You could use that cam and some Rhoads lifters to take away some low rpm duration. Some say they work. You did mention 2:23' now and higher gear with a overdrive later. Automatic. Worse case senario, you would have to put in a higher stall converter to help it work better. If you have a automatic of course. I guess the issue isn't a rough idle in drive.