Ive just got my Ali petrol takn and i was wondering do i need to have a vent pipe put into it for my pinto unit? plus how to i put my donor sender unit on the tank?

The tank will need a vent or it will suck up. You can either make a vent in the tank or get a vented cap.

As for the sender there are various ways. I made up a colar and threaded some holes in it. Bolted that to the tank with counter sunk screws and bolted the sender on using the threaded holes with loads of sealant.

Some ppl use self tappers into the tank.