[Marty Phipps]

I'm hoping all you long time Pontiac folks can clear something up for me.
All this talk of different head numbers is starting to give me a headache [img]/infopop/emoticons/icon_frown.gif[/img]
What in all of your opinions, would be the best Pontiac production heads made?
Because of the scarcity of the RA1,2,3,4 etc. heads please don't include them.
So far I now seem to have a set of #46, 47, 6x, and 7k3
heads all for just one motor(my 428)
At the moment my 7k3's have the largest valves in them, but there seems to be a question of what cc they are.
Please, Please, oh Please
Some one shed some light on this poor hapless former chevy boy

[Marty Phipps]

I'm hoping all you long time Pontiac folks can clear something up for me.
All this talk of different head numbers is starting to give me a headache [img]/infopop/emoticons/icon_frown.gif[/img]
What in all of your opinions, would be the best Pontiac production heads made?
Because of the scarcity of the RA1,2,3,4 etc. heads please don't include them.
So far I now seem to have a set of #46, 47, 6x, and 7k3
heads all for just one motor(my 428)
At the moment my 7k3's have the largest valves in them, but there seems to be a question of what cc they are.
Please, Please, oh Please
Some one shed some light on this poor hapless former chevy boy

[Tom Vaught]

Put a set of good 6X heads on the motor after a
cheap Butler port job and forget about them. The
good 6X heads are better than any of the normal
non ram air stuff.

[larry davis]

I agree w/ Tom.

IMHO, the 6X-4 or even 6X-8 heads are the best to use. Esspecially w/ a little $ invested in the right port work, minor milling, & larger exhaust valves.

Marty, check the AC boss of your heads, it will have a stamped 8 or 4 there. The 4s have smaller chambers thus higher compression.

[Blackcat]

I would run the 7k3's if you aren't concerned about headers. Bigger valves and good breathing.
Same as the 71 96's. They would make around a 9 to 1 motor. The back fall is the lack of outer bolt mounts for exhaust. [img]/infopop/emoticons/icon_wink.gif[/img]

[dyingbreed]

While we're on this subject, I have a set of 6X heads on my 78 T/A Pontiac 400 engine. I'm not sure if they are the 6X-4 or 6X-8 heads and I want to find out. Larry Davis made mention of checking for the 4 or 8 stamp on the "AC Boss of your heads." What does this mean (AC Boss?) and where is this located on the heads. Please be as dercriptive as possible.

Sorry for my ignorance,
dygingbreed.

[Alex]

Dying,
Here's a link that should Help Ya

http://members.tripod.com/futom/id59.htm

.......Al

[rasilverbird]

I have the 7K3's for my 455 rebuild. I'm planning on using headers, so can't the outter bolt holes be tapped?

I'll start a new post for this....

[ February 08, 2002: Message edited by: rasilverbird ]</p>

[Marty Phipps]

I just receive a call from the machine shop that's got all of my 428 stuff.
After CC'ing the heads and factoring headgasket crush?, etc., etc.
With the 7k3 heads I'll be running a compression ratio of 9.5 to 1
My 46 heads would have put the motor at 12.5 to 1
The 6x heads haven't show up yet, but I would think the compression of the 7k3's would be about right for a street driver.