It's not the lack of potential.
For a streeter;
It's a double-edged sword, involving cubic dollars or cubic inches.
If you are not limited to a certain size engine,
It's just way easier to start with more bore and or more stroke.
The 360 for instance, falls together with off-the-shelf pistons and readily available heads, already at 10.7 Scr, and you can easily use the 2.02 intakes or bigger. and you do not have to rev it very high to get a modest 400hp. and, at that power-level, it will still have a mountain of bottom end torque. That's just 42 cubic inches.
What's all that gonna cost to get, with 318 cubic inches? Yur gonna have to supercharge it to compare, which is, for most of us, Cubic dollars.
And I guess it goes without saying, a streeter is a two gear car at most. Most of the time, yur gonna crack 80mph at the top of second. So all that power is kindof moot.
The chassis is gonna need cubic dollars to take advantage of that. Our typical big-tub A-bodies can't even handle 300.
The smaller tubbed cars are roasting tires at 250.
So then, 460 is just so much bragging rights, until you get the chassis on line.
Finally, 460 hp in a 318, is gonna take a lot of rpm, and that means a lot of camshaft, which calls for a lot of compression ratio. This cam will have so much overlap, that it will barely idle and you can forget fuel economy.
Whereas 460hp in a 360 requires a much much smaller cam, with a lot less overlap. and will thus still have a modest bottom end, that doesn't waste all it's raw fuel out the headers.
And for a car that spends a lot of time cruising, like mine once did, 330hp was a chitload of fun, still overpowered the 295s, or more, and still returned excellent fuel economy. MORE than any 330hp-318 could ever achieve.
If you want that kind of power, (460hp) using a 318LA, you are gonna have to sacrifice the entire bottom end, get at least another gear in the auto-trans, get a high stall, and stick a big gear in the back, and most of all, yur gonna need a way of hooking that to the street.
That's just the way it is.
These are extra sacrifices/extra costs, that more cubic inches might not need. and for a two-gear streeter, IMO, this is as good as insane.
But, I'm staring at it with an empty wallet.
If you own Ft. Knox; have at it.
Or
the smart money is on supercharging it.
These are my opinions