Just about all heads after the 60's will be 1.94, with the exception of the 305 heads which are 1.84 I believe.

I agree with Monte, do some research about heads, i.e. chamber size, heavy or light casting, center or perimeter valve covers, intake bolt holes, etc.

I might suggest going to a local auto machine shop and see if they have some have some heads that someone brought in and never claimed. They should also be knowledgeable about fitting your needs.