I have a 1984 GMC 4x4 pickup 350, 3 speed overdrive (manual), did a vortec 350 engine swap and was wanting to know how to wire the alternator, old one has the big post and flat 2 wire plug ( red &black wire), the 97 vortec motor has a big post and a 2 wire plug red & black wire, now it charges hooked up red to red, black to black, but when the truck is shut off the alternator make like a real faint hissing sound. thanks for the help.