Exhaust buildup

[Yamahaulin]

What causes this buildup in the exh port of my car. I haven't run it in a month and took to turbo header off to replace with a new one. I noticed this crusty white build up in the ports. I have run some 110 leaded fuel less than 1000 miles ago. The motor is new maybe 5000 miles total.

 

[spyderdrifter]

Almost looks like frost..

 

[Yamahaulin]

Kinda but it's not frost. I can wipe it out but not sure what has caused it.

 

[iceguru1114]

Based on what you've told us, looks like the leaded fuel may be responsible. I've certainly never seen that with pump gas. If you figure it out keep us posted.