Valvetrain failures on C-5 Z06 Corvettes

[Richard L.]

I'm in the market for a FRC and have found that Z06's are prone to broken valve springs with predictable catastrophic consequences. What I want to know is: 1) how prevalent are such failures, 2) is there a way to avoid them [no high RPM's?], 3) are there VIN number sequences or specific years I should stay away from? 4) do the heads have to come off to replace the suspected springs? and 5) is there a reliable supplier of better springs?
One way to avoid all of these headaches would be to simply buy a regular 350 equipped FRC but since they only sold in 1999-2000 (around 6,000 units), there are few to be found for sale out there. So I'm searching for answers regarding Z06 engined FRC's.
Hope to hear and learn from your experiences.
THX
Ric

[Patrick H.]

Re: Valvetrain failures on C-5 Z06 Corvettes

They have done extensive tracking over on CF:

https://www.corvetteforum.com/forums...ailures-3.html

[Joe L.]

Re: Valvetrain failures on C-5 Z06 Corvettes

I'm in the market for a FRC and have found that Z06's are prone to broken valve springs with predictable catastrophic consequences. What I want to know is: 1) how prevalent are such failures, 2) is there a way to avoid them [no high RPM's?], 3) are there VIN number sequences or specific years I should stay away from? 4) do the heads have to come off to replace the suspected springs? and 5) is there a reliable supplier of better springs?
One way to avoid all of these headaches would be to simply buy a regular 350 equipped FRC but since they only sold in 1999-2000 (around 6,000 units), there are few to be found for sale out there. So I'm searching for answers regarding Z06 engined FRC's.
Hope to hear and learn from your experiences.
THX
Ric

Ric-----


The original part number for the 2001 Corvette LS6 valve springs was GM #12565117. For 2002-2004 the part number was GM #12565313.

Both of these were discontinued and replaced by GM #12706568. The latter was discontinued and replaced by GM #12713265 which remains available.

The part number supersessions in this case imply that there may have been some problem with earlier springs and further imply that the problems have been worked out with later part numbers. If I were going to replace the original springs on an 2001-2004 LS6, I'd use the 12713265.