Black soot inside exhaust pipe

[BOB1969]

I installed a new ZZ383 with 750 Holley in my 69 Camaro. I have noticed some black soot deposits inside the exhaust pipe tips. Does black soot indicated I am running to rich or is my timing off a little. Time advance is 31 degree. Car runs good but I have noticed the soot build up.

[camaro608]

rich its unburned fuel

[Scott Parkhurst]

Try going down a couple jet sizes on the primary side. It'll probably clear it right up. If it runs nice, you're probably real close. A couple jet sizes might be all you need.

~SP~