318 timing chain.....and why the engine should come out.

Years ago I had a 69 teener that slipped the chain on starting once and when it didn't fire, I hit the key again and it backfired. 1 Bent exhaust valve many bent push rods and no teeth on half of the cam sprocket.
I was young then, but I dropped the pan. Changed the pump and pickup, new gears and chain, reconditioned heads and valve train, never touched the botton end, added 4 Bbl and headers and ran another 50k before pulling it for a 340. Never smoked.