360 Heads- which ones should I expect?

The casting # from '77-'86 is 4027569.
The casting # '76 is 3671587 (same as '73-'74).
The casting # from '75-'76 (mid year) is 3769974.
The casting # from '73-'74 is 3671587.
The casting # from '70-'72 is 3418915.

Hope it works out for you,