I may be having a senior moment, here, but don't think there is a gasket between the pump and the block. Both mating surfaces are machined and it doesn't hold that much pressure. I'm sure someone will correct me here shortly if I'm wrong.
Thanks for posting. I was beginning to think no one would post a reply. Yes, there are two gaskets. One is for the pickup to pump (Felpro #72516) and the other is for the oil pump to the block (Felpro #70083). They are very similar in thickness and size. The one that mates up to the block is a little larger (more gasket material, the holes are the same on both of them).
I don't think there will be a problem, but I thought I would ask before I put the pan on this weekend.
You can get or have them order the right ones from any parts store Fel-pro makes both they are differant but not much.......why take a chance with oil pressure for a couple of bucks. I just did mine when I changed the pan also think about changing the pump drive rod while you have the pump out. Get the heavy duty one.
Use the gasket that appears to fit best. I also use a bit of blue Loctite on the bolts. My 68 289 managed to loosen one bolt and the gasket crept out a little. On a 60,000 mile motor. The symptom was that oil pressure was absolutely normal below 4000 Rpm. At or above that speed, oil pressure dropped to zero (and almost gave me a heart attack). Luckily I noticed it immediately and was able to idle back home without ruining anything. I don't care to discuss what I went through to track down the cause of the problem. I think I gave myself a bald spot in that time.
You can bet that ever since that episode I make damn sure that gasket is in there and well secured whenever I put an engine together.
I doubt I'm the only one this has happened to as I've seen racers safety wire these particular bolts. The same people are likely to tack weld the oil pickup to the pump, another good idea.