I am installing a roller cam in a gen IV 454 mag. Its installed at 0 meaning no advance or retard. It has been rebuilt 30 over and has keith black replacements. I do not have the part number yet. Does it sound right that there is an interference on a stock bbc? It is only kissing the piston as it opens.

Cam specs. Int/exh
Adv dur 271/279
dur @.050 224/232
valve lift .591/.601
lob sep 112

i think something is no right,i would pull the heads and clay check piston to valve clearance after you find out why it is hitting.are you sure cam is in properly?the only way to know for sure is to degree it in.

The valve should not hit the pistons in a stock configuration with that cam.. Could be installed a tooth off, I see the pistons were changed with 30 over. are they stock replacement pistons? or slightly domed? are they hung on the rods correctly? bottom line is the cam alone, and installed correctly should be fine. IMO

The cam timing was off. There are 2 zeros on the crank sprocket and I lined up the wrong one.

I jumped a chain once on a big block. My valves loved it.

Yes when you drink and build motors you see double. Then you see too many timing marks and things get assembled incorrectly. Nice catch while it was on the stand. .