I don't think so as the early A manifolds have more of a rearward twist than those... The only way to tell for sure is to test fit them in one with a v-8 in it...
I have had temptations to go v8 with my valiant wagon but I already have the mega rare slant six 4 speed bellhousing and I have a lot of money into the slant already.
A v8 seems exhausting but If these manifolds would fit then it would rekindle the temptation because it would be one less thing to have to buy