Started my first repair on a 4G63 in a Cat GC25K. Been doing overhauls on tractors and industrial equipment for 30+ years. The unit has no compression on 3 & 4. So we are gonna pull the head and go from there. I have researched and can't find much on timing up before I pull the head. We've only worked on domestics (farmall, IH, JD, Oliver etc) and this is my first OHC! This unit may require a full OH but head is coming off first per client request then pull engine if required. Any help on timing specs would be great. I see a dot on the single belt pulley that drives the dual cams but I can't find anything else. Also looks like the distributor is bolted on with the intake manifold so is there an additional step there? Thanks in advance