[john walker's workshop]

what year and model? add it to your signature for better answers.
assuming it's a turbo, at 65K, it has nikasils, and a ring job with goetze rings should be fine, if the pistons and cylinders check out ok. worn guides and worn/crispy stem seals is the usual reason for oil consumption. disassemble all the heads and check them out. if you replace the guides, you need to cut the seats. moving the heads closer to the case results in a lineup problem with the cam thrust plates. you could trim the chain housings an equal amount, but the chains would have more slack. do-able, but don't get too carried away.