1971 Scamp stock 318

Most bang for the buck......
to do what?
Most bang, to get off the line, is a 2800TC.
Most bang, after already moving at ~20 mph or so (depending on the rear gear), would be performance gears.
Most bang, for Part-Throttle operation, or fuel-mileage, would be more cylinder pressure.
Most bang for passing, would be the right second gear ratio.
The most bang for a downshift into first at ~32 mph, would be a combination of Stall and gear ratio.
Most bang for spinning tires off the line, would be Stall, gears, and a 4bbl, all three together.
Finally;
Most bang for second gear power after 3500rpm, THAT would be a cam.
In order for the bigger cam to work, the engine has to be able to process the additional air. That means, more air in = more air out. So you gotta consider the 4bbl,the headers, the dual free-flowing exhaust, fresh cold intake air, AND the heads; ALL as a set.
see note1


Start with;
Ignition timing,then
Stall,then
gears and SG.
Next; 4bbl, and free-flow muffler, both together, then
fresh cold air.
Next;Compression ratio,cam/kit,headers,and dual exhaust; all together; or
solid lifter cam/kit, headers and dual exhaust; all together

Note 1
The thing about cams is, with no other changes;
the next one size bigger (a size being ~7*) same type cam (hydraulic FT in this case) will, at the same LSA, bump the operating range up about 200 rpm, at the expense of the lower rpm losing power.. So if you bump your operating rpm up say 3 sizes from the current 240*, to say 262*, your power peak will want to move up from ~4200, to maybe ~4800. but your heads will be hard done-by to make any power up there.
In any case if you gain 600 rpm at the top, then you will also give it away at the bottom...
So 600 doesn't sound like a big deal right? Well with 2.76 rear gears, the power peak moves from say 46 mph to 53mph , and that's a lot. Depending on your actual power, that 7mph,could be 2,3 or maybe even 4 seconds.
At the bottom, each cam size will cost you about 200 rpm in stall,so if your teener was fine with an 1800 stall with the factory cam, then the 3-sizes bigger 262 cam, will want ~2400.
So, when you think about cams,you just gotta think about the whole air in/air out,combo. see note 2
The LA318 is stuck with a pitiful 8/1 NOMINAL Scr. And that means it could be less, even 7.6. . So when a cam is considered, you also have to think about a TC, and the final cylinder pressure, and the rear gears; all as a package.
If you don't, you will have just joined the club of thousands of unhappy 318 owners who all did the same thing.

note 2
Here's how it works;
the typical 7.8sCR-318LA might make 135 psi @sealevel with the factory 240*cam with an ICA of 48*.
The next bigger cam, with an Ica of 51.5, drops the pressure to 132
The second bigger cam will drop to 128
that's 7psi already!, or 5%.
But guys want to go straight to the 268/276, HFT 340 cam, with an Ica of 66*, and that drops the pressure into "Total Lazy-Dog"territory of 116psi/about a 15% pressure loss! Don't do that.
They all say it ain't so bad, but I tell you. it sucks/ don't do it.

Happy HotRodding