What is the big deal about having 906 heads?

[resq302]

Ok, I admit that I don't know much about cylinder heads.  At shows, sometimes people would ask me what heads I am running and aside from the fact that they are cast iron heads, I don't know.  Yesterday, I put the correct valve covers back onto the car and found out that I have 906 casting number heads.  From what I hear, everyone compares everything to this head.  What is the big deal about them?  Is there any cons to having them?  If it matters, they are on my 383 HP engine in my 69 Charger.

[firefighter3931]

Ok, I admit that I don't know much about cylinder heads. 

Shame on you Brian ! 

The 906 was considered the best performance head of the era but the reality is that most BB heads flow almost identical. The 906 casting is correct for your 383 if that matters. 



Ron

[resq302]

Ah ok.  Now I understand.   

[firefighter3931]

 

[resq302]

Just another stupid question about the 906 heads.  How typical was it for the studs that thread into the head for the exhaust manifold to strip out?  I have at least 2 that are stripped and had to go one size up on the one and the other had to go 2 sizes up.  Also, since they went into a water jacket, were they prone to leaking around the studs?

[firefighter3931]

Brian, stripped threads and busted bolts are fairly common....many of them have been drilled and retapped due to rusted studs that were broken off while trying to be extracted for replacement.  Usually, the studs seal well with a little pipe dope or sealant. When using header bolts....it's a different story. Those are more problematic and can be a PITA. I use ultra copper high heat permatex on header bolts with good results.


Ron