318 Power, with real street manners ?

Well, IMO, use the engine you want to use. I have zero issue with the 318 & think that building what you have vs. spending more money on what you don’t have is a winner. While the 318 lacks torque and requires a little more into the build than a larger engine, there really is nothing wrong with the 318.
Yeah. I'm sure it would need rebuilt. Was pulled because of internal engine noise. But have not pulled it apart
Mild 14 second car? Depends on if it needs a rebuild or not. No rebuild needed ? Then I would;

600 cfm carb on a dual plane, headers into a 2-1/2 exhaust
(FVtory iron intake and a TQ would do well.)
Excellent ignition
Cam @ .050 of 220 with more exhaust with matching valve springs.
(A good example is the Comp Cams XE268 Hyd. cam. Or similar speced cam.)
2200 stall
Shift kit
3.23 - 3.55 gears
Wide tires

If it needed a rebuild, same as above but the new slugs would be the KB hyperU’s or a forged slug set at or very near zero deck.

Calculate your compression ratio first!

Iron head at NO higher than 9.5-1 will be great.
Then again you could always follow Ma MoPars advice by clicking the below link in my sig area!
Yeah I'm sure it will need rebuilt. Have not yet pulled it apart yet. If it needs a lot of $$,depending on how much $$ at that point I may $$ ahead to look for a 360/ or maybe a magnum 5.2 or 5.9. But Have not looked a what the "real cost" of buying and converting to a magnum really are...have no idea.
I forgot to mention , my 318 is a roller block/but dose not have the roller cam , or the other roller parts. Not sure what year , just don't remember. It was given to me. But was pulled because of engine noise.