Back before roller cams were readily available, drag racers applied all types of techniques to the cams and valve train for that extra edge. Hand stoning the exhaust opening ramp was one of them.
You take a naturally aspirated engine combo and supercharge it. Same cam, same valve events, but the s/c engine will have a different blow down and will need more. Basically cracking the exhaust open sooner allow time for exhaust decompression. Exhaust and intake valve size ratio and exhaust port flow are factors as well.
Since we are naturally aspirated and our valve ratios play very well together, the exhaust port flow is super, delay the exhaust opening late as possible. Long rod, long stroke like our engines have play VERY well with delayed exhaust. I dont remember the exact degree of crank angle to piston speed for a 4.6l, but iirc its over 10° from the top or bottom. Opening the exhaust 10° before the bottom means 20° of dead timing to decompress otherwise known as blow down.
Now something like a pushrod 302 with short rod, short stroke, and giant 4" pistons,....the blow down opening will need to be longer, meaning exhaust valve opening sooner...more duration. No dead crank angle space like a long rod, long stroke.
This is one of those engine aspects that have to be explored rather than buying it. Each and every combo is different.