I have a 1991 740 Turbo Wagon with 229k currently off the road in the garage as I am using a new VW as a daily driver. The Volvo runs well, but there are always problems popping up. I have put a lot of money into it in the last few years and after a month or two, there is another repair to be made. Now I need a new battery and the engine was sometimes hesitating when slowing down and accelerating again. The idle is good, but not great and the throttle body builds up carbon really quickly. I wanted to ask if I should have the engine rebuilt and everything worn replaced all at once, or maybe do a V8 conversion and put in a Ford 5.0 V8. Is it worth to overhaul the car or try out the V8 (maybe eventually put on a supercharger). It is not coming out of the garage for awhile as I do not need two cars on the road. I love the car and I do not think it would be worth much to sell. I like to do something with and make more reliable again. Any suggestions would be appreciated.