1972 Blazer starting issue

[tabs2471]

Hello all, I'm running into an issue I cannot figure out. My 1972 Blazer wouldn't start one day and I used my charger to charge the battery and started it up fine. Drove it for about an hour then parked it back home. While it was running I checked that it was charging and the alternator was reading 14.7 volts....felt good about that. Wouldn't start again. Since then, due to process of elimination, I have changed battery, cables, ignition switch, starter and solenoid! I even added a ground off the main ground from battery to alternator bracket....ran that to frame. I am absolutely at a dead end! It turns over real slowly and almost sounds like the timing is off. How could that happen when the last time I drove it, it ran fine. Almost frustrated enough to sell it at this point however I love the damn thing so no. Any help would be greatly appreciated.