OK i got the sled going well (finally), replaced intake and exhaust gaskets then i tried running it without the air box again... Turns out the airbox was clogging it up abit

Has way more power and no bogging

Now i have a question regarding the temps the engine should run at. It has 2 rings that fit under the spark plugs to get the temps. I've had it read as high as 500f when i was pushing it, is that alright or too high?