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07-22-2017, 11:03 AM
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#1 |
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Member
Join Date: Nov 2016
Location: Indianola Washington
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Hollow stem intake valves
Are hollow stem intake valves legal in stock if they were not OEM for the engine? As well is it legal to change valve stems sizes in stock but keeping the same valve angles?
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07-22-2017, 11:26 AM
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#2 |
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Senior Member
Join Date: Feb 2002
Location: Southeast Michigan
Posts: 906
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Re: Hollow stem intake valves
In the rule book , it says "Any aftermarket steel valve permitted, must retain stock head and stem diameters" . Says nothing about hollow stems being illegal .
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07-22-2017, 07:30 PM
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#3 | |
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Veteran Member
Join Date: May 2006
Location: Murfreesboro TN
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Re: Hollow stem intake valves
Quote:
It is NOT legal to change valve stem size. Not in Stock Eliminator or Super Stock. But hollow stem valves are legal, even if not originally equipped. We run them in everything, we use Ferrea.
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Alan Roehrich 212A G/S |
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07-22-2017, 07:48 PM
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#4 |
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Senior Member
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Location: Southeast Michigan
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Re: Hollow stem intake valves
In Super Stock the valve stem needs to be the stock size , but aren't you allowed to use necked down stems near the valve head , like the Manley "Pro-Flo" style valves ?
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07-22-2017, 07:51 PM
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#5 | |
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Veteran Member
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Location: Murfreesboro TN
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Re: Hollow stem intake valves
Quote:
Yes, they can have an undercut stem behind the head of the valve.
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Alan Roehrich 212A G/S |
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07-22-2017, 11:59 PM
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#6 |
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Member
Join Date: Nov 2016
Location: Indianola Washington
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Re: Hollow stem intake valves
Titanium valves can not be used but are titanium retainers legal?
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07-23-2017, 11:10 AM
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#7 | |
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Member
Join Date: Mar 2016
Location: Crete, IL
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Re: Hollow stem intake valves
Section 10A says "Titanium prohibited". Although that's vague and you don't know if they're referring to valves only or all of valve train. But I know when the Drag Paks came out they had titanium retainers and were allowed one year to remove and replace with steel (I read that anyway). Everyone uses lightweight tool steel retainers for the most part.
Quote:
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Todd Gross 3323 FS/E,F |
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07-23-2017, 03:46 PM
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#8 | |
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Location: Glendale, Arizona
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Re: Hollow stem intake valves
Quote:
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