Just picked up a Bob Jackson road bike today. Frame number puts it at 1990 according to the handy chart posted by @FalconSS. Well maintained, already a fine ride but components are a real mix - the majority being Shimano 600 Arabesque (front & rear derailleurs and chaining/ cranks). Reading up about Arabesque these components must have pre-dated the frame by 10 years. The question is whether to complete the Arabesque group when replacing bog-standard brake levers and calipers or to start again with a group set from circa 1990 and in all probability get much better performance. Also stick with Shimano or look elsewhere?