Mopar 318 heads

do do a compression check and make sure all is ok before proceeding
also how's the timing chain

what the mopar muscle article (link above) said
We elected to go with a Competition Cams XE262H, a hydraulic grind spec'ing out with a gross duration of 262/270, delivering 218/224 degrees open time at .050 inch tappet rise and .462/.470 inch lift on the intake and exhaust sides, respectively. (218 is 10 degrees bigger than the 340 Magnum cam nut look how much shorter the seat to seat is- close to 16 degrees adjusting for lift ad adv duration see why I say the 340 smog cam is LAZY- it is giving an EGR effect)

Another good choice would have been Comp's smaller XE 256H, which shows a somewhat " fatter torque curve down low." (for stock gears)
"Higher camshaft should be reserved for combinations with more flow potential from the cylinder heads and a higher level of static compression."

Now personally I'd never use a comp under 274hl
here I'd use the Lunati 250 or 256
compare the lift with the comps in the article you will find similar areas under the lift curve but shorter seat to seat
you pick up torque on a low compression build
Big as I'd go is the 256 Howard
all these have different LCA's so there are some choices
For my on personal engines I've used the Jones 256

holding off on the cam is a good idea unless yours is trashed
and do not spend money on roller tip rockers
there are other more important things- like suspension and stopping