The modern day aftermarket stuff (unless you spend a TON) is mostly crap, I would not trust it. I would much rather have a good used factory piece. The metal is much better. JMO.
X2 on modern replacement parts, most are made off shore.
If you must buy new spent the $350.00 and get a name brand SFI, centerforce or mcleod make quality products.
Some mcleod flywheels have bolt on weights that you can switch between neutral balance and external balance.
FYI if you you have a neutral balance, and need a 143 tooth 11" flywheel one out of at of a 318 in a 4wd in the 70's will work.
I have an extra.