Wallace Racing

Pontiac Head Codes

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Pontiac made closed chambered heads until 1967.In 1967 Pontiac made some open chamber heads(i.e. 061).After 1967 the heads were open chamber heads.

Exhaust Crossover Port Matchings
With Head	And Manifold	Use Gasket
1965-71	1965-71	1965-71
1965-71	1972-79	1972-79
1972-79	1972-79	1972-79
1972-79	1965-71	1965-71**

** Use sheet stainless steel block off plate.

In 1975 Pontiac started stamping extra numbers (1/4" tall) on their heads.These head numbers represented chamber sizes.They are usually stamped on the machined pads by the valve covers.

Head codes - 51,5C,6X,6S,6H
2-	101cc's	probably special 455 head for 455HO T/A
4-	91 cc's	350/W72 engine; - 77,78,79 stick T/A's engine code WA,WC,& PWH; - 77/78 W/72 auto T/A code Y6 (77) & X7 (78); - Can-Am's with T/A 6.6
6-	114cc's ?	any 455 head (75-)
7-	98 cc's	400 AIR (5C or 6S)
8-	98 cc's	400 standard (5C or 6X)
9-	91 cc's	350 AIR (5C or 6S)

(Let me know if you have any more of these.)

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Year(s)	Engine	HP Rating	Head #	Valve Size	CC or CR

Wallace Racing

Pontiac Head Codes

Head codes - 51,5C,6X,6S,6H