78 Grand Prix build

I don't have any pics, but I've spent the last week with my frame on some saw horses stripping and priming it. I have reinforced nearly all of the factory welds. Today's major accomplishment was starting and finishing boxing in the c channels! Tomorrow I've got some grinding to do, and I'll be reinforcing the suspension mounting points with DOM tubing.

Slow moving! Finally committed to something today though, pulled a complete 1967 Pontiac 400 out of a Bonneville. Its got 061 open chamber heads which were a 1 year only casting, 2.11 intake valves. I'm pretty excited. I'll see what it looks like during disassembly, but it looks like its never been apart.

Short block is still intact and will have to wait until tomorrow. Heads are off, good news is cylinders are all standard bore.
When I removed the valley pan, I found two 2" pieces of broken push rods sitting on the lifter valley. All of the push rods installed are in tact.... I also found 1 more busted 2" end in the oil pan. Looks like the push rods were replaced without retrieving the broken pieces and tearing down to inspect for damage? What is the likely cause, cam with too much lift or long push rods?