Unless you build your low-compression 360 engine to take advantage of header-tuning, a header all by itself will not make much power.
The power is in the combination of parts, released by the cam-timing events, augmented specifically by the effectiveness of the overlap period.
The 268/276/114 factory 340 cam has a very modest 44* of overlap, which is stifled by the cast-iron manifolds.
Same cam, cut on a 108 LSA, will have 12 additional degrees of overlap, and now yur up to 56* overlap, which is on the threshold of making power, but you need headers to unlock it.
However, if most of your driving is done at sub 3500 with 3.23 gears and a stock convertor, headers won't gain you much performance, even with the 108 cam, (over 340 logs) ................... because the engine is stuck at rpms too low to make the not-long enough primary tubes work; the tuning is way off.
But um, if you have a 2bbl 360 cam, in that 360, even with a 4bbl installed, headers cannot help you because of the very modest valve timing events.
IIRC the 2bbl cam is 252/260/112 with overlap of 32, count 'em, 32 meager degrees of overlap, so headers can't do much with that in the first place, ......... never mind that the chambers are so huge as to cause the signal to completely dissipate right in that ~105cc pit.
People keep telling me that hi compression is NOT required for a streeter. And of itself it may not be .......... except for the fact that, the flip-side to low-compression, is that those 105cc chambers on a 360 are a prime example of what not to do, cuz, it just about kills the vacuum signal from the header tuning, and it(said signal) gets lost in the chamber and never gets thru to the intake plenum.
However, with the right combination of parts, headers can not only make power, but also, help you get relatively great fuel economy in steady-state cruising; which with a long-stroke 360, can easily surpass a smog-era carbureted 318.
It don't much matter how great your tune is, on that 318 smogger; with the same final-drive ratio, I can get more mpgs with a hi-compression/modestly-cammed, 360 with headers, than the exact same car with a well-tuned low-compression 318, that has a total chamber size of over 95cc; and, if you drop the final-drive ratio down to sub 2.0 with an overdrive, your engineered 360, can absolutely smoke even the best-tuned, 2.45 geared, factory low-compression 318. Ask not How, ask Why; Answer; those zero-quench monster chambers ain't helping the 318, whereas 75cc on a 360, are killer efficient, partly due to the tight-quench required to get the chambers down to 75cc's..
But, I got side-tracked a lil.
The point is this;
With the right combination of parts, you can build your 360 to hit all the bases of Torque and Power, WITH performance, AND fuel-efficiency, in an A-body...... but
the 8/1 slugs, together with the monster open-chamber heads, will have to go ................. and headers will absolutely have to be on the parts list; as will an overdrive.
