I have had 3 GRP .21's 1 stock tuned, 1 modded tuned and 1 modded non-tuned. They all run at about 225. My first GRP .21 tuned ran at 225 for 7 gal until I sold it. It still had plenty of power and ran great. If I lean them out they get up to 240 but this is too lean power suffers and no smoke. A friend of mine says his .21 tuned runs all day long at 165. The other variable is the temp gun. I have had an expensive temp gun read 30 degrees cold and cheap temp guns read within 5 degrees. Test the temp gun with 50% ice and 50% water and see what it reads. Bottom line the temp doesn't matter as long as you tune to performance and smoke you can never go wrong. I have been told by my engine moder to nod and smile to the guys that say 225 is too hot for a GRP. Good power with crisp acceleration and good smoke out of the pipe at all speeds is all you need. Besides every engine is different. All 3 of the GRP's that I have owned have needed different needle settings by as much as a full turn, theres just too many variables. Performance and pipe smoke
