<VV> Battery charger with 50 Amp "Engine Start" enough ?

[Charles Lee]

OK, now I may have killed my 67 Monza 110's battery or possibly the starter, 
starting it so many times ?

I replaced the battery, same slow cranking, so I got a Battery charger with 
50 Amp "Engine Start" and no internal battery that needs charging first.

Still, same slow cranking.   Maybe 50 Amps is not enough (Sears has an 80 
Amp model) ?

Maybe I've worn out the starter ?

Thank you for your support !
Charlie