1955 thunderbird runs bad, have 6volt positive ground system

check the timing....try 7 degrees BTC and see if this causes knock...quite near knocking is where we want to be for maximum output...also you DO have a distributor vacuum advance which should get a Silicone replacement vacuum line and bellows should be checked to see that it's rotted and need to be replaced...the screen at the base of the fuel pump is kerjobbled with rust and should be disassembled and blasted clean with air~....what else? all systems should be cleaned...given a squirt of tri-flow or lubricant and carburetion set by an olde tymer~...find one...they are still around~

this probably will not help...but is a romp~ https://www.youtube.com/watch?v=ni8kuIxyY_U

check the compression...check and compare leak down times~

I'd check wiring to the ignition first (check voltage at the points, distributor ground), then distributor advance (with timing light), then carburetor itself.