Heads

[mikewb]

anybody know what head this is? i found this number 8986889X or 3986339X

[joesgarage71]

339X is a 1971 307/350 74 CC head
 couldn't find the 889X you must have read it wrong 3's 9's 8's look alike and sometime the casting gets sloppy. If they are near the same date there most likely from the same motor.
 Steve

[mikewb]

was trying to figure out what valves

[red4wd]

I saw them listed as 1.72 and 1.50

[mikewb]

is that a bad head to have?

[Captkaos]

What are using it for?

[mikewb]

there on my motor right now. 350

[Captkaos]

I meant when you say are they bad in what reference are you asking?  If you are asking if they are a good performance head then the answer is no.  If you are asking if they are a good head in general, they would be a good low rpm head.

[mikewb]

i meant for performance

[mikewb]

should the numbers on both heads match or are they different?

[Captkaos]

The should[/b] be the same on both sides.

[mikewb]

I have these . left 3946813 right 3986339X

[joesgarage71]

3946813= 69-79 350 truck. And you know the other one. The casting numbers should match but I have seen untouched motors that had different heads on them from the factory.