pds

Hi, I have a 1986 Nissan Cabstar (also known as Civilan or Atlas is some countries) equipped with the ED33 engine. Although the truck is quite old, it's in a rather good condition and has only made about 160.000km. Nonetheless, we had to replace the head gasket about one year ago and now there is coolant in the oil... I suspect it's the oil cooler that is coolant with oil... but can't be sure until we start to disassemble it... This could be a simple fix, but the problem is that it's being extremely difficult to get spare parts for this engine, and impossible to get a replacement used engine... As such, we are considering to replace it with another "compatible" engine. Does anyone knows if Nissan has another engine that can be a straight forward replacement for this engine? Someone told me that there is an engine from the Nissan Patrol that could fit with minor modifications, but didn't know the exact model. Does anyone knows what engine could this be? Thanks in advance!