\i am looking to buy this 1977 chevy pick up tommorrow but i was curious it seemed pretty sluggish what could cause this?
the guy said the engine was a 305

 

It's 32 years old. When Are you feeling this sluggishness? On takeoff? Are there any other noises? More details.

 

Furthermore, is this going to be a beater, transportation, a mudder,or what?

Assuming the engine isn't beat,(a really bad assumption to make if you're on a tight budget)
I'd say the top four suspects would be :
1:Clogged air & fuel filters
2:Clogged tranny filter
3: Beat Distributor cap,rotor,wires, and spark plugs(possibly as well as the coil and other ignition parts)
4: Low tranny fluid

If the vehicle's been sitting for some time, of course, you'll play hell getting the old gas completely flushed through the system. There's a lot of variables here, once again, assuming you're mechanically handy, and it's a well-preserved truck, you may have a fine vehicle.

I've gotta agree with 92chevysilvy. Got any more details?