# Piston id help



## MidnightAuto (May 28, 2018)

Hi guys- I recently bought an endoscopic camera to connect to my iPhone. I wanted to get a view of my piston tops to see if I could surmise what the previous owner had dropped in. Snaked the camera through spark plug hole and pictures are from #1 and #6 chambers. The motor is a 1964 421 with the 77 heads. The motor seems to run fine on 92 octane. So I have two questions, (1) do these pistons look stock, or are they dished a bit to drop my cr (and why I seem to have no isssue with 92). And (2) the #1 piston looks a bit discolored at top - is that normal or sign of pinging danger? I have never heard this motor ping, although it is free flowing exhaust that is pretty loud. Thoughts appreciated, thank u.


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## PontiacJim (Dec 29, 2012)

Not factory and it appears they are dished pistons to lower compression. Top of the piston looks normal as you will get carbon deposit on the tops - they do not stay shiny like new for very long.


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## MidnightAuto (May 28, 2018)

Thanks for confirming Jim. I continue to be impressed with po decisions. He had passed away so did not get to talk about the car...


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## geeteeohguy (Feb 2, 2008)

What Jim said. Custom dished pistons. Lucky you. Whoever built that engine built it to live on today's gas. Win-win for you!!!


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