Yeah the last thing you want to do is run that engine. Don't even start it have it cranked up onto a flat bed and towed to your house/shop/dealer. I would bet it is the timing chain. Pull the valve covers and check them out.

When was it last done? M116's should be done every 10 years / 100k miles.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200