318wr, head over to the /6 site, see what others have done and then decide. You can get respectable power from one, enough to keep up with and merge in and out of traffic.
Strangely one of the best running/6s that I have experienced "stock" was moms death warmed over, mouse gray, 79 LeBaron. I don't know what gear it had in the back, but it was completely stock as originally built, super 6 edition. And was a fantastic mileage car. Good road trip car.
After adjusting the valves, tweaking the carb and the timing to "what it wanted" regardless of the under hood sticker wanted, actually ran pretty damn good. Later Mom had an 84 5th with a 318 and no matter what I did to that one it couldn't get out of its own way. Dad's 82 gran fury with a slant actually"wasn't bad" in the get up and go" department either.
Now when I had my 79 D100 short bed and it ate its cam gear (something I've often read about but only ever had happen that one time) I found another/6 and stuck in there. Another 225 (as they did come in 2 other displacements). Same truck and what a difference in a bad way. That 2nd one had me wishing I had simply replaced the cam in the original engine and carried on. That replacement/6 was definitely a dog no matter what I did to it, drank oil and blah. It was a running used engine that I don't know where it came from or miles or maintenance history. I didn't have that one in there long, only long enough to find a 318 freshen that up and get all the"conversion parts ". I had it bored, put a set of badger pistons in (cheap ones) reassembled, got an MP cam (last 3 numbers were 757 or 759, whichever one it was I went "one cam smaller " than what I originally was looking at, and was suggested by others to run. That 318 ran GOOD.
As does the one in my son's wagon that used to be in my 83 D250. The only thing "360" about that one was I put in a stock replacement 360 cam from melling the SPD25. Along with a magnum (EQ) head conversation and standard "performer" intake (not "rpm" or airgap, none of this.just a plain performer and carterbrock 600 carb. I couldn't believe the number of people who thought I was lying about it being a 318 as I used and abused that truck like the 1 ton it should have been. But I wasn't. Stock original factory assembled 318 short block, only reason I pulled the pan was to retrieve the pushrod that I dropped on assembling the top end.