I recently purchased a 78 K10. I have been taking it to work each day (about a 25 mile commute) on the highway 70-75 MPH and bombing around town on the weekends. I never had a problem until last night when I plowed. Everytime I shut it down it would diesel (briefly). I looked at the temp guage and it was not even 200 degrees (sat at about 195) when shutting down but it still dieseled. I know plowing puts more stress on the motor and the plow doesn't help with air-flow through the radiator, but the temp quage was not hot. I'm assuming it is high combustion chamber temp causing the dieseling. Fuel igniting from heat and pressure rather than ignition spark. What are possible solutions and what do you guys think. I was thinking of going to a one step colder spark plug and/or going with a colder thermostat. Do these sound like a good idea or are there drawbacks? And it there any suggetions you have? Thanks in advance. It has a Carter carb of unknown size on it, and I was also thinking of maybe making some adjustments, i.e. richening just a hair to lower combustion temps, but I would like some input.