Which needle are you adjusting? make sure it's the low speed needle if you are just letting the car idle, or the high speed needle if you are doing a WOT break in. Also make sure you don't have any air leaks. An air leak will make tuning and overheating your worst nightmare. Make sure all engine fastners are tight and I always try to seal opening around the carb to prevent air leaks. If you're not already, continue your break in with the body OFF. Also, it's a good idea to get a temp gun. The spit test will give you a general idea of your temps, but an I/R temp gun will give you pretty accurate numbers. That way you have a good idea just how hot or out of tune you may be. Hope this helps.