65 dart 273, No fuel from pump to carb!

A back fire suggests the engine is firing at the wrong time.

You resealed the engine. I'm assuming you removed the distributor.

It can go back in correct or 180deg out.

Also the plugs I assume you pulled the plug wires off the plugs or dist cap

The rotation is clockwise for SB cou ter clockwise for BB.

Be sure the firing order is correct.