i never seen that ever before.
but it says: "....which have eliminated the need for external adjustments. This change allows for easier "bolt-on-and-go" performance. The floats have been factory-set for optimum fuel levels at 3 to 6 psi of fuel pressure and should never need adjustment. If you're running over 6 psi of fuel, a fuel regulator is required"

so that means you were flooding the crap out of it with your 8psi and no adjustment ;-)

on that carb i couldn't even tell you how to adjust the floats. so ignore it and just ause a regulator at 6psi

 

All floats are adjustable - the new Holley that you have is not EXTERNALLY adjustable but the floats can be adjusted by removing the fuel bowl and bending the tang on the float - that is how they are set at the factory and anytime they are rebuilt. Running 8psi is (as you now know) way too much. Your carb has a "blow-out proof" power valve so it is probably not ruptured.
Using a by-pass regulator is a great idea.
BTW: when checking timing NEVER count the vacuum advance when calculating overall timing. You only count the initial and mechanical timing in the "total" advance. To find out how much advance you have disconnect and plug the vacuum line to the distributor and run the engine up to 3500 rpm and measure the advance at that rpm. Most SBFs run best with 34 degrees BTDC "total" advance (not counting vacuum advance). After you set the timing to 34 @ 3500 rpm then lock it down and turn the engine off and reconnect the vacuum advance.

 

Distributor timing is very complex, "total" advance is only a small part of it.

 

for the protection I think this is only for carb backfires, not for fuel pressure. But I'm not sure on that, anyway, not to worry.

you probably don't have a test stand, but you can do it all in car as well since fro what I read I assume you have a timing gun where you can check the advance.
When crank turns twice distributor turns once.
so 1000rpm distributor is 2000rpm crank (engine)
and 10 degrees on distributor is 20 degrees at crank.

From the table you can see you want max 20degrees mechanical. so if you set the distributor for 12 degrees, you want
~10 degrees at 2000
~16 degrees at 2800
~32 degrees at 4000
and no more advance from there. Some engine want a different curve, but for a stocker those are the values to go for. I believe as well that your engine will probably best power at around 32-34 degrees max at 4000rpm.
the curve itself you can regulate with the springs and tabs. depending what distributor you have

 

k ty im gonna be changing it in a few weeks we have parked car and gonna start taking the front end apart and get the front end total rebuilt with new parts