not sure but don't think those are j heads. if they are you should have 2.02 intakes. agree with 1BadMirada, j heads i have seen had a big j cast on the exhaust side. have seen big valve heads with a Z or an O cast on them, same size valves but not actual j heads.

 

The Direct Connection Engine bible "Caroll Shelby's Speed Secrets" says these are 1976 360 castings.