I have a possible good deal on a 3vze Head to get my 4Runner back on the road but they are noted to fit up to 1991 models. As my ride is a 94 version, I really don't know about compatibility.

Anyone know the specific the differences if any on early versus late model heads. There appears to be something since the timing belt is also different between the 2 versions?

 

the timming belt is only diffrent as the tensioning method used.

there are some minor diffrences in thinks like the distrubutor and water distrabution block, and the upper plenum connections. but i think this was limited to the 88-89 versions.

but as for the heads, AFAIK they are identical and swapable.

 

I have a '91 4Runner. When my heads cracked, they replaced them with heads from a '94. I would think you could go the other way too.