History of "Stage jr" heads... please

[TIMS87GN]

Can someone give me some background history of the Stage Jr. heads. I now own a set and I am wondering where they came from, why they aren't in any literature and whether they can be ported more than production heads. I know you can port out the Stage 1 heads because they are beefier in the ports, is this true with the Jr?

Please educate me and anyone else interested. Thanks!

 

[GNVAIR]

Stage Jr heads as I recall were basically the same 8445 castings that were used from 83-87 without the EGR/heat risers drilled.
They were used for non emissions applications such as test motors, export or marine usage. As far as their metallurgical content or whether they are thicker still remains to be seen as no one has cut one open yet.
The Stage one heads even though the used the 6293 casting number had some features that regular production casting heads did not have such as thicker deck faces, no EGR/heat riser, smaller end water passages to help strengthen the deck.
There may or may not have been more "meat" around the valve seats/bowl areas.

 

[S2V6RACER]

So there is a difference in these "JR" heads vs. authentic Stage I iron heads?

 

[EightSecV6]

Originally posted by Ted A.
So there is a difference in these "JR" heads vs. authentic Stage I iron heads?

Pretty much identical to a stock 8445 head, the casting still has the jagged hole cast in the center exhaust port just like the stocker does. The ONLY difference is the port is not drilled from the intake mounting surface into this exh EGR port that is cast into the head. Real Stage1 heads have the same exh port on cyl #3 and #4 as cyls 1,5,2 and 6 do. The bigger question would be "how did they get the name Stage 1 JR attached to them?" For a professional race or hot street port job, the port under the valve needs to be filled and blended just like the factory head does,take a look at a Champion iron head and you will see what I mean.

 

[Jeff Harrington]

Have a set of these heads here, and there is no holes that you could fill in the exhaust bowl. They look just like 8445 heads without the holes drilled.

 

[EightSecV6]

That would be a "stage 1" head correct? not a stage 1 jr????

 

[Jeff Harrington]

Don't know, my son bought them as stage I jr heads. They do have 8445 casting number on them.

 

[EightSecV6]

Originally posted by Jeff Harrington
Don't know, my son bought them as stage I jr heads. They do have 8445 casting number on them.

Someone brought me a pair of stage1 "jr" heads or whatever they are being called, they had 8445 castings and were identical in all respects, they had the egr hole under the exhaust valves on cyl 3 (or4) and the only difference was that the port was not drilled through into this hole from the intake manifold face. The hole under the exhaust valve is cast and then it is drilled through. I would think yours should have the hole cast below the valve with 8445 on it but if it doesnt, I dont know what you may have!

 

[SPOOLN]

Maybe those could be the Stage 2 Jr heads

 

[TIMS87GN]

Well I removed the valves in my heads and I can confirm that mine don't have any EGR provisions in the exhaust bowl area. But I agree that they look identical to the stock heads....just no EGR stuff, and the water jackets are bridged. I took snap shots too in case anyone is curious.

 

[frankg]

I just ported a set and they are the same as stock 8445's except no EGR holes anywhere. Frank

 

[mec108]

Bill; Have you or anyone else ever heard of a Stage 1A head???

 

[9SECVSIX]

Stg 1 heads

The real Stg1 heads like those listed in the BPS were a 6293 casting that had considerably thicker decks that the 8445 heads, bridged water jackets. no EGR holes anywhere. They do not have the hump in the intake port and will out flow the 8445's on the intake port.
I used a set for years. They have the #10 cast below the center exhaust port.

9sec.