360 Magnum Heads

I saw a comparo on U-tube where they dyno'ed a factory rebuilt 440 with iron heads. Then within hours dyno'ed it again but with alloy heads. The difference was very small. What she mighta gained in power, she lost to the lack of increased cylinder pressure.
Some books say that alloy heads suck so much heat out of the chambers that you need an extra half a point of Scr just to break even. I think it's actually more.
To get the most out of alloy heads, you need to increase the compression ratio. But not just the Scr, more importantly, the cylinder pressure. So if you are not gonna fix the pressure issue, and with only a mild cam, Ima thinking alloy heads are sort of a waste of money, on such a combo.

Now let me tell you about that.
If you build it right, you can get the cost of the pistons and boring back in fuel costs in just a few years, and enjoy the torque and power for the whole time.
I built and am extremely pleased with my alloy-headed hi-compression (11:1) 360, and it burns 87E10 100% of the time, with full ignition timing. It has run three different cams, with pressures set between 180 to as high as 195 psi, with no detonation. The build wasn't cheap but it has gone over 100,000 miles now, since 1999.
I would sacrifice the Airgap, the Holley, and the MSD, to get some hi-compression pistons into her. With a mild cam, you won't need any of those; just throw any old junk up top, and the MSD is overkill as well.
My 360, with KB107s came together with a deck height of .012 clearance which is 2.5cc. The pistons are flat-tops with 5cc eyebrows. The Eddies were 63cc. the .028 gasket is 6.8cc for a total of 77.3cc
If your engine cleans up at .020 your swept will be 744.6cc. Therefore your Scr would be;
(744.3 + 77.3)/77.3= 10.6 to 1
Put a mild cam into that with an Ica of say 58*, and she will generate about 180psi, or more depending on your local elevation.. I guarantee you, that on the street, you will not care about how much power it might be making, because it will be so much fun to drive.
You could even run it with a 2bbl up top, for most of the time...... I kid you not.
If for some reason you have to deck the block, I would pop the pistons up out of the holes and run the FelPro .039s at a Quench distance of .030/.032.
This engine has the potential to put your A-body into the 12s on street-suspension.
The small cam will make monster torque, and if you tune it right, has the potential to make great fuel economy. And it will like an overdrive so you can gear the back to optimize Second gear.
Those heads, together with the right small cam(and springs), will have a looooooong flat power curve, that will allow her to rev deep into the 6000s (I shifted mine at 7200, just cuz). So then you gotta do some oiling system mods to not lose a rod, cuz Ima thinking after the first time you try it, you are gonna be addicted.

But, if you are building this for street-duty, and
are dead-set against opening up the bottom, and
are sure about the small cam; then
IMO,
I would leave the expensive alloy heads on the shelf.
By themselves with no supporting changes, they might be worth one cam size, at full-power. But they might actually lose power at low to mid rpms, because of their ability to take heat out of the chambers.