It is probably a broken valve spring.
Chevy did not make a 350 in 2001. The last 350 was built in 1999.
.003-.005
What_is_the_push-rod_placement_for_a_1996_lumina_3.1_engine
Cam bearings, Rod and Main bearings. That will be all of the bearings required to replace when rebuilding a 350 engine.
You can put grease on the rod and gently push it into the block. the grease will hold it in place for a good amount of time.
The rod should be 5.75 inches; assuming the correct year, size, and stock cam, fuel pump, etc.
5.7"
Sounds like a rod bearing. Time for a rebuild job.
Just turn the engine over while you are pushing on the rod with your finger until the rod goes up in the block and starts to come back down then stop, and install fuel pump. Turn engine by hand. Put a ratchet and socket on the balancer bolt in the middle of the bottom pulley. Turn it that way.
The rod torque on a Chevy 350 V8 depends on which size rod bolt you have. On the 3/8 rod bolt the torque is 45 ft/lbs On the 11/32 rod bolt the torque is 35 ft/lbs
5.7"