Hi, how can i tell if the C heads on a 68/69 are big valve or not, still on engine? Thanks

 

I remember hearing or reading somewhere the big valve heads had a X stamped on the machi ed rocker arm stand

 

Sorry, you'd have to pull the heads and measure the valves. They used the same castings and just cut out the seat for the valve size desired. The 1967 had an application code stamped in one head. But 1968 and newer didn't. If you knew for a fact they were original... and you knew the engine was a factory 442 or Toronado engine they would be big valves. But for an engine that's 50 years old who knows what's been done to it over the years.

John

 

^^^this!

 

Are there any identifiers on the heads to indicate correct year or model?
-Christopher

 

Not really.

If the heads came off of a 1967 motor, there will be an engine unit number stamped on the front of the passenger side head. This will tell you the original application - of that one head, anyway. Other than that, there are no external distinctions, and definitely none on 1968-69 heads.

 

Old thread I know but I have been scouring the interwebs for this very thing. I just confirmed this on my extra C Heads with A.I.R. They both have an X stamped on rocker arm stand like Matt mentioned over # 1- and 8-cylinders. That being said, I have yet to actually measure the intake valves to be 2.072 so may still be a myth? I have read about the X in a few places now so am fairly confident it is a tell for big valve heads.