I have a '85 block w/mech. fuel pump. The pump is from an '83. I believe the timing chain cover was changed to accept the mech. pump. (I bought the motor done) My issue is, my power steering pump bracket now hits the fuel pump. I was going to use a later model serpentine set up. I didnt realize the pump would interfere. Keep that in mind, if you are planning to go serpentine