vortec swap

[tmac]

i have a 84 chevy c10 pickup im trying to hook up the altinator the truck came with a 305 i put in a 350 vortec my problem is i cant get the altinator to charge . the altinator that originally came with the truck had 1red wire on the back and a 2 wire plug on the side of the altinator 1 was brown and 1 was red the red wire is slightly bigger than the brown wire. now on the vortec altinator it has 1 red wire on the back and 1 brown wire on the side which leaves 1 red wire that i have no idea wer 2 hook it