Wallace Racing - Pontiac Cylinder Head List

PONTIAC POWER RULES ! ! !

If you know the code number, try my new head search

Chart to mill Pontiac Cylinder Heads
Chart of C.R. of Pontiac Engines and Heads
C.R. Percent Power Loss

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 1973 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 ID Location

The following are 73-74 heads

4X-1H uses 4.881/4.870" valves
4X-1H are 455 head with 114cc, 2.11/1.66" valves and pressed studs.
4X-3H are 400 4bbl head with manual transmission, 98cc, 2.11/1.66" valves and screw-in studs.
4X-4H are 400 2bbl head, 1.96/1.66" valves and pressed studs.
4X-7H are 400 4bbl with auto trans, 98cc, 2.11/1.66" and screw-in studs.
46 are 350 2bbl/4bbl heads with about 86cc, 1.96/1.66" valves and pressed studs.
4C-5 are 350 with AIR, 1.96/1.66" 86cc, pressed stud.
4C-9 are 400 with AIR, 1.96/1.66", 98 cc, pressed stud.

*All heads cast on or about May 7, 1973 received threaded studs.
 So, take the head above and if they were cast after or about 5/7/73,
 the "pressed" applications will be "screw-in".

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5C heads were installed on engines until around mid 1975 then dropped

-5C-4- 1975 350 4bbl, 2.11/1.66" valves, 4.960/4.949" valve length,
 30/45 degree seats, threaded studs, 93cc

-5C-7- 1975 350 4bbl AIR, 2.11/1.66" valves, 4.960/4.949" valve length, 
 30/45 degree seats, threaded studs, 93cc

-5C-8- 1975 400 4bbl, 2.11/1.66" valves, 4.960/4.949" valve length,
 30/45 degree seats, threaded studs, 101cc

-5C-9- 1975 400 4bbl AIR, 2.11/1.66" valves, 4.960/4.949" valve lengths,
 30/45 degree seats, threaded studs, 101cc 

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The 6X castings started being installed on engines after about 2/21/75

6X-4 350(and 77-79 T/A 6.6), 93cc, 2.11/1.66"
6X-8 400, 101cc, 2.11/1.66" 
6H-6 455, 124cc, 2.11/1.66"
6S-7 350 w/AIR, 93cc, 2.11/1.66"
6S-9 400 w/AIR, 101cc 2.11/1.66"

The 6X-4 and 6X-8 were the only heads used after 1976. 

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(Let me know if you find any more information on these codes or any not listed.)

Pontiac Intake Manifold Years Interchange

1957-1958

1959-1960

1961-1964

1965-1979

Does not apply to 301 or the RA V

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