The engine has tested for low compression. It starts great cold but has some history of stalling at temperature due to not making enough power. The van was given a tune in September 2024 and it was drivable at the time although it was only driven in town (last driven December). The writing is on the wall for the engine as it is for any original engine on one of these vans. The low compression is due to poorly sealing piston rings. Piston ring service is an engine-out service so a good time to refresh seals/rings/gaskets anyway. My mechanic informally quoted the service as $7500 (parts and labour). The price can go up depending on how much you want to replace inside if your intent is to bring everything to 10/10. On the top end another option is to get a new/rebuilt crate engine. These engines are tested before shipment so it could be a DIY job for the person who is comfortable pulling an engine an dropping in a fresh one. These engine designs are 40 years old and much simpler than a modern motor. My mechanic said the labour to install a new/rebuilt motor starts at $2900 (17 hours labour charge) if you don't fancy DIY.