Muffler temperature normal range?

[kfosburg]

Hi,

Just upgraded to some new SSI stainless heat exchangers on my 71E.They look and sound great!

I've noticed lately (even before the SSIs) that my [stock] muffler "seems" to be hot. The aluminum back panel between the bumperettes is very hot to the touch and there's lots of tinking sounds as things cool off.

After a 10 minute spirited drive last night, I quickly measured the temperatures with my IR gun and found that the muffler itself was around 420 degrees F. Basically uniform left to right. The stainless exhaust was lower - around 250, but that could be attributed to a different emissivity value of stainless versus flat black muffler...

Mixture is uniform left to right and front to back and ranges from 10 to 13 as measured by my wideband. Timing is correct.

Is this within normal ranges? Perhaps is my muffler slightly clogged up inside?

Thanks in advance,

Karl