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#1 |
Junior Member
Join Date: Sep 2008
Location: Moore, OK
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I found a set of heads that match the casting number I need except it has an x at the end of it. Is this still a legal head? What does the x mean?
NHRA/GM allowable casting numbers: 3998991 or 3986339 found a set with 3986339x thanks,
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Tim Wilson HR/SST 4301 |
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#2 |
VIP Member
Join Date: Jun 2006
Posts: 3,417
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3986339---1.72 intake/1.5 exhaust-74CC--- 68-69 307 eng
3986339X--SAME SPECS(int/ex/cc)---71 307/350 eng 3998991---1.72 intake/1.5 exhaust--75CC ---68-69 307 eng 72-73 307/350 eng hope this helps--Comp387 |
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