In the photo below, the cartridge on the left is the original dud cartridge out of a '66 Astro-Sonic with the newer silver changer with metal tonearm. The cartridge on the right is a current Pfanstiehl replacement; which, is nothing more than a "crosley cartridge" with a bracket glued to it.
The new cartridge is supposed to sub for the old one; but, it's not happening in my case. The new cartridge is slightly wider than the old one and is twice as thick; so, the bracket won't come close to being flush with the tonearm mounting hole. I really wish that if these manufacturers are going to make a substitute cartridge that they'd make it just like the original, instead of slapping a metal bracket on the rear of one of their standard "crosley cartridges."
On the VM website, Gary has a '70's-era EV cartridge with a flip over stylus that's supposed to be a direct replacement for these older cartridges (the wiring harness is also included with the cartridge). I suspect that one would be the best overall choice and I may order one, unless you have some other suggestions.