I just bought a 69 firebird with a broken engine. One of the valves floated and punched a hole in the piston (also turned sideways so the engine couldn't turn). I pulled it a parts, replaced the bad parts and pulled the cam today. I noticed it is a original GM cam that has been regrind. The GM cam says its from 2001. I don't know when it was reground. The cam is stamped with XR288.

When i search it all I can come up with is a cam for a big block. Is it possible this will run in a 5.3L? What are your thoughts on if how this will run?

BTW, my guess is the valve floated because they left the original truck heads with valve springs in. I plan on getting a set of LS6 springs.

Thanks for your help.