I was having a conversation with one of my customers who works on a lot of these cars in his area.
He was tuning a 440-6 in a Challenger that he had just put the motor together for, and got it running.
He uses a wide band gauge in the car to get them dialed in.
The carbs he was using had the OE calibration, the motor had iron heads set up for proper quench, and a cam that would put the DCR right about 8.0. This car runs ex manifolds.
With the OE jetting(OE metering plates), the motor was in the high-10’s/low-11’s a/f ratio at WOT.
He installed some Pro Max secondary metering plates with jets equivalent to the holes in the factory plates.
WOT a/f ratio was now in the hi-14’s/low-15’s.
It required going up about 5-6 sizes to get the a/f ratio into the mid/hi-12’s at WOT.

We have encountered the same thing on the dyno here when the OE secondary metering plates get swapped for the replaceable jet type.

One of the 440-6’s I had on the dyno, which had small headers, a Comp 280 cam, 346 heads...... ended up with 65 jets in the center carb(mid-13’s a/f ratio at part throttle cruise), and 86/86 jets in the end carbs(hi-12’s/lo-13’s a/f ratio at WOT).
This was a motor that was only making 500tq@3900/424hp@5200.

With regards to the feeling that the motor isn’t as impressive feeling as maybe the OP had hoped.......
Imo, 450hp, 3.23’s, low-ish stall speed, vs carbs, full weight car....... that’s a combo I wouldn’t expect to “feel” all that impressive.

The first 440-6 I had anything to do with made about the same HP, but less TQ by a fair amount than the OP’s build.
It went in a 70 Challenger RT/SE, 3.91’s, tight TA 10”(about 3400), small tube headers.
Owner brings the car down to the shop after getting it installed so I could take it for a little test drive.
First 6bbl I’ve ever driven........ and it’s the first “hot rod” type motor the owner has ever had.
He thinks it’s an animal......... I think it’s more like “eh”.
I told him it should go 12’s based on the dyno numbers, but it didn’t really “feel” fast to me at all.
They had some old slicks mounted on rims, brought the car to the track..... put the slicks on...... went 12.30’s@113.
Way quicker than it felt.