Cupped washers

I'm searching for those washers to attach the hi-po exhaust manifolds. So far, what I have found are sorta pricey, but that's not the problem currently. How many are required? I've gotten differing information, depending on where they are available. I've seen that 4 are needed, 1 on each corner. I've also seen that as many as 12 are called for.
Can anyone give me a solid number? Also, is there a good source for these. I have all the studs and sleeve bolts, just missing the cup washers.
Thanks!
Look a photos in the shop manual. My recollection is 4