On my truck I used manifolds off of a 1979 blazer, they worked like a charm. I'm sure that there are several years of full size truck manifolds that would work. You want the passenger side to dump at the rear of the manifold. On the drivers side you want it to dump between cylinder 5 and 7. Now these worked fine on the older small blocks. What side is your dipstick on ? Sorry I don't have any pictures to show you right now.
For every dollar that you spend on your truck, put one in a bank account. That way in the end you will have built two things that really mean something to you.
Good things may come to those who wait, but only the things left by those who hustle.