General Cylinder Head Flow Numbers discussion

[SSDiv6]

Originally Posted by Stan Weiss

Ralph,

Thanks. Didn't I hear a couple of years ago NHRA got something like a FARO, touch probe / laser scanner for checking stock ports?

Stan

With core shift and with the high number of different cylinder head part numbers for the same engine combination, it would make it very difficult.

This is a true story...
Many years ago I got a call from NHRA asking me about technology to shrink metals, especially cast iron. The reason was that there was a particular engine combination that every time the engine went through tear down, the cylinder heads were compliant and at the next race, the car would go faster.

So, NHRA purchased a pair of the suspect cylinder heads from a junkyard, sends the cylinder heads to a trusted shop to have them built to the rule book guidance and when they poured the cylinder heads, the port volumes were bigger than the suspect cylinder heads!

I explained to NHRA that during the casting process, a temperature differential or the abundance of Ferrosilicon will cause shrinkage of cast iron. The reason why many racers check and flow lots cylinder head castings. ...or the cylinder heads were spray welded to add more material.