My version of a factory parts build 318

If a small bump in a 318’s performance is being sought and as I read it, for a truck????

Mill the stock 318 head, a 3 angle valve job with the stock valves is good (and cheap vs installing 360 valves, even though I’d suggest it, but it’s pricey.)
Use the 360 cam. Everything else reuse from the 318.

Add an upgraded ignition, dual exhaust, headers or not, use an H pipe. For a quite muffler, Walker has the Quite Flow & for a quite rumble, there Sound XF mufflers. The longer the case the more quite they will be. A size of 2-1/4 inch exhaust pipe is all you’ll need for this set up.

IF the short block needs rebuilding, use the earlier 318 pistons. They offer more compression vs the smog years.If there not available, the KB slugs and a slightly thicker head gasket can be used. I’d look for a 9.0-1 ratio for 87 octane use.

The J yard jewel I would not use for a truck.