Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
first of all you will notice my bad English, i am sorry but i'll try to make me clear. And i am sorry too for the poor look of this build, it's my first one.
This build, as you can get from the title, my main spell is Power Fist! DPS Blitzcrank In late game you will be spamming 500 damage 3s - 3s plus the speed of overdrive for DPS.
So Manamune is essential for your damage and for your survivability, now it gives again 2% of your max mana as damage plus it increases your max mana. This last passive is also important for your survivability because of your Mana Barrier. How much max mana you have then higher barrier you will get. This way you last longer in the team battles.
I prefer Swiftness because i want speed. But If you want to play in a more defensive way ninja tabi or even Mercury's. Although i won't pick berserker's for more attack speed you already haver overdrive. Blitz's DPS is an extra for Power Fist! Not your main power.
Then Sheen for your extra 100% damage in Powerfist then, 150% with trinity. Which also gives you mana (damage and survivability) and health.
Now i mostly choose impaler because of the armor, critical strike and it also gives you more damage. But Youmuu's Ghostblade I think it would also be a good choice, mainly, because of is active and Critical Strike. Or even if You want to last longer in the battles and not buying more damage, Frozen Heart would give you armor and mana (damage and survivability) or Banshee's Veil for magic resistance.
Grab -> Punch -> Overdrive(DPS) -> If it's taking damage of Static Field's passive wait and then Static Field's -> Punch Punch Punch
When i am against some character i can't win one a one give him a punch run (if you want overdrive) while he is chasing the cooldown ends Punch! run again if he quits you grab him and Punch! and you now perhaps can kill him or your teammates are closer.