Timing Chain Cover crankshaft opening is the wrong size

for $100. IT can be replaced..
1968 DODGE DART Summit Racing SUM-163273 Summit Racing™ OE-Style Harmonic Dampers | Summit Racing

While its not the factory original, and I have no plans on racing my convertible this
should get the job done.
The replacement doesn't have the cup cover on the backside of the harmonic balancer is that an issue ?


The original front side is attached