I just installed Hooker shorties and let the engine idle for an hour to cure the header coating. While it was idling I checked the temps of every tube for the heck of it and found that tubes 6 & 8 are running at about 300 degrees and the rest are at around 450 -480 degrees.....the engine sounds smooth when I gun it......or am I just thinking too much?

 

Shooting the tubes with a heat gun isn't 100% accurate and coated tubes block a lot of the exhaust heat. The only way to get exact temps from all 8 tubes is with 8 EGT sensors. Using a heat gun can tell you if you have one really bad, hot or cold cylinder. Hot cylinder is running lean. Cold cylinder is dead.

 

What he said... OTOH they may show those 2 cyls being rich. You could quickly test for that by just swapping the injectors on that side and seeing if the temps follow the injectors. If the low temps stay the same, then the cause could run the gamut from totally insignificant to an early indicator of something serious: the coating is a bit thicker on those, or there's some other problem such as a blown head gasket between those 2, or just about anything in between.

I'd agree though, the difference you report isn't all that abnormal, given the number of potential random factors affecting it.

 

thanks guys....it is possible I sprayed the coating on those tubes thicker than the rest

 

I had the #'s 6 & 8 spark plug wires switched at the cap...lol