Ohhh but no one knows the tjmax temp for desktop processors only notebook temps are released so its just a guessing game. I normally go by Tcase temp but I'm not as smart as these guys.
According the intel the max temp for that processor is 72.72C http://ark.intel.com/products/75048/Intel-Core-i5-4670K-Processor-6M-Cache-up-to-3_80-GHz?q=4670k