No Power

I bought a 1990 ford bronco with a 351 windsor in it. I dropped a new motor in it new plugs, new spark plugs wires, distributor, cap and rotor. replaced all gaskets on the engine replaced air filter and fuel filter. I know the new engine i put in the 1990 has power i had it in a 1981 and could pull any hill as fast as i wanted this new bronco i have hardly any power i put it in 4 wheel drive and it really doesnt have the torque or anything to move the tires. I did notice that my u joint that is next to the transfer case from the rear axle is really worn out and i have alot of play alot. was wondering would that be binding up at all and causing power loss? well I took the cats off and they cloudy how good should you be able to see through the cats? I could just clean out the cat and make them hollow i had that done on my 81. nothing was really wrong with the old engine it just had 175k miles on it and i like to have a reliable vechile up 4wheeling....yeah everything on this 1990 is new except the exhaust system i can kind of see through the cats but it is really hazy