new balancer too tight

Tried searching for this problem and coming up short. Got a CAT balancer(I know, this is likely the culprit) and trying to install it on a 1965 273 crank. Even using the installer tool from Autozone I can't get this thing to go on. It starts to go on, then goes slightly crooked and gets real difficult so I stop.

On the inside of this new balancer there's a significant step where the inner diameter gets smaller. The original balancer has a smooth transition and never hangs up like this new balancer does. Haven't busted out the BFH yet because I've heard of splitting balancer hubs(the CAT website even mentions this). Did crankshaft hubs get smaller after 1965?