I think it is a later head because of the kidney-shaped combustion chamber, but I am not sure.

The best/easiest way to tell is if the ports are oval or teardrop shaped... The early had oval ports, while the later had teardrop shaped ports.

Another thought... The exhaust manifold would have 1 bolt in the middle for an early head, while the later have 2 (like the pic).

"A young man who does not have what it takes to perform military service is not likely to have what it takes to make a living." - John F. Kennedy

Proud owner of an 88 Montero (with a blown engine).