SBM Edelbrock/Speedmaster Head Data

[polyjohn]

In homage to PBR here is some of his work on the SM head.
You have to look carefully at the port roof to see the extra work he has done.
''Seamless'' I would say and a magician without a doubt...RIP
I guess his head had more roof work than yours Earlie-A?

''

 

[polyjohn]

When I saw the CNC heads on his thread it got me all spooked.
Bad machining and an even bigger port bowl was a 'step backwards' to me!
You can see quite clearly the 45 degree seat has been damaged, NOT good at all.

 

[Earlie A]

In homage to PBR here is some of his work on the SM head.
You have to look carefully at the port roof to see the extra work he has done.
''Seamless'' I would say and a magician without a doubt...RIP
I guess his head had more roof work than yours Earlie-A?

View attachment 1716337304

View attachment 1716337305
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View attachment 1716337308

He was certainly a master of the SM/Edelbrock style head. I don't know if his roof had more work than mine, but I bet it had better work than mine, lol.

 

[Earlie A]

When I saw the CNC heads on his thread it got me all spooked.
Bad machining and an even bigger port bowl was a 'step backwards' to me!
You can see quite clearly the 45 degree seat has been damaged, NOT good at all.

View attachment 1716337306

View attachment 1716337307

I have seen other high end heads that have that same washboard appearance in the combustion chamber. I don't quite understand it. It looks like sloppy work to me. I know ridges like those in the picture that are in close proximity to the seat and top cuts are flow killers on the flow bench. The only way I could see that being beneficial is if helps re-atomize the fuel for a more efficient burn. If those kinds of ridges help, I would think they need to be oriented in a particular direction. The orientation of the ridges in those pictures seem to me to be computer generated to follow the area that needs to be machined. Maybe someone can correct me, but I'm still leaning toward sloppy work. A Trick Flow chamber is CNC cut with a much, much smaller stepover (distance between cuts). It is a nice looking chamber.

 

[gzig5]

I have seen other high end heads that have that same washboard appearance in the combustion chamber. I don't quite understand it. It looks like sloppy work to me. I know ridges like those in the picture that are in close proximity to the seat and top cuts are flow killers on the flow bench. The only way I could see that being beneficial is if helps re-atomize the fuel for a more efficient burn. If those kinds of ridges help, I would think they need to be oriented in a particular direction. The orientation of the ridges in those pictures seem to me to be computer generated to follow the area that needs to be machined. Maybe someone can correct me, but I'm still leaning toward sloppy work. A Trick Flow chamber is CNC cut with a much, much smaller stepover (distance between cuts). It is a nice looking chamber.

The ridges are an artifact of the tool diameter and program step over. Takes a small step over to make a surface cut by a hemispherical tool to look smooth. Smaller stepover increases machine time 2x-3x. Time is money.

 

[Earlie A]

The ridges are an artifact of the tool diameter and program step over. Takes a small step over to make a surface cut by a hemispherical tool to look smooth. Smaller stepover increases machine time 2x-3x. Time is money.

My point exactly. Profit matters more than quality = sloppy work.