BB Chevelle...
 

The valve train was definitely the weak link in the hi-perf big blocks...replacing springs, keepers, retainers, seals and ideally new aftermarket one piece valves is good insurance.

Dropped valves, broken springs and keepers were responsible for a lot of CE motors.

-wilma

This is what the original owner to my L78 conv wrote me


"Yes, I dropped a valve twice, and the street racers/wrenches, said to put after market,
better valve springs in, Chevrolet wouldn't do it under warranty. So the third time a valve spring broke, I ran it at high RPM, till it quit, put the valve in the piston. A mechanic that worked on it the third time, told me Baston took it upon themselves, to upgrade the valve springs. Not sure if that was the truth, but never broke a valve spring after that".

Those factory springs are like wet noodles, float the valves causing the rest of the damage.


To quote ssl78.. I cant imagine intentionally blowing up an engine on a new car just to get new springs. Why not purchase and install them himself?

----Both times I broke valve springs on my 1966 427/425 Corvette it was on start up. Guess I just lucked out as the inner held the valve up at idle. After the second I had the main Corvette tech at Bob McDormans replace all the springs. He was racing the same combo and put good springs in.......Bill S

Because purchasing and installing them himself was $$$ out of his pocket, and if the dealer somehow found out about it later, bye-bye warranty. Blow up the engine and all the expense is covered by GM.