I'm curious if folks interest would be different if these heads are purchased at full retail. They definetly seem appealing at the black Friday sale price. At full retail and most likely needing to switch headers or manifolds from d-port to round is the KRE or Edelbrocks a better choice.

I agree these are going on a clean out the garage "spare parts" motor:)

Thanks Paul

I am pretty anxious to see how the "$300 CNC mod" plays out on Skip's heads using his friends flow bench.
Not so much the max flow number - but the uniformity throughout.
They will definitely hit bigger numbers than As-Cast

If they come within 5% balance I'd consider that pretty close to a miracle.
And very acceptable at the price point.

Skip probably plans to test every port and disclose his results.
Other sources might just only disclose the highest flowing port and leave the rest out.
Especially if its a lopsided result.

If the results were to become too lopsided , then its a " CNC jump-start porters head"
- on a head that isn't supposed to allow much porting -
ouch

I understand what you have stated about the weakest port and the head having limitations.
Hopefully they applied enough wisdom to let that problem-port be the focus/high water mark in their overall CNC program.
And didn't make any other port exceed that particular port's capability.

Give it he|| Skip
:D

Did you mean to type 1.5% and 2.0%? Appears you had a little core shift.

Lol..... I meant almost exactly the same

When we do the math we multiply by 1.015 or 1.02 using a calcultor. So a 380 cfm head will flow between 380 and 386.

If I multiply by 1.5 a 380 cfm head may flow as much as 570 cfm..... That's probably SM's acceptable range.

Paul,
He said "%". Your 1.015 = 101.5% and 1.02 = 102%. So you are both saying the same thing in different ways.

Stan

That only works if every head that is manufactured is the same. Even Pontiac didn't have every head casting the same.

The other thing is the engine sees the total intake track air flow. So unless every intake manifold runner flows the same there will still be differences to each cylinder.

Stan

Pontiac had more than one mold too, for mass production.

I think all these are from the same mold and have the same problem on the same port of each head.
Or at least that is what it has sounded like to me so far .

If Paul sends out a set of his NASA Spec 0.015 % variance CNC heads and somebody has them cross-checked afterwards , and finds 20cfm variances in certain intake ports - he gets a bad rep.
And an angry customer

If these CNC SM heads get flowed and have 20cfm -or more- variance in certain intake ports it will hurt their reputation also.
At full retail price they would be very very hard to sell.

I was originally going to use some ported 6X-8 heads on it but my old back does not like lifting iron heads anymore:)

Don't forget every header pipe or exhaust manifold port better be same length and flow the same.
Everyone likes to focus on the heads but seem to completely forget about the stuff before and after the heads has a huge effect on the heads.

Thanks Stan, I understand. I think he was just kidding. I know I was.... A SM head has a snowballs chance in H#*l of flowing 380 :D

Yes, I was kidding and see you edited your post so that may be a missing piece of the discussion for some.

And the is why it is funny. That would be 0.0525CFM variance on a 350CFM head which might be rather hard to measure.

EHTTFMF's!!!

SMCNC to the Flow Bench Bit ches !

Skip,
Does your buddy's flow bench have the means to do any velocity probing?

Stan

Stan I do not think so, unless he added and extra manometer.

Interesting, there is a pair of Speed Master heads for sale in the classified section. They were listed last August.... For a lot less than retail price.

2 New pairs for sale in PY Performance Parts section .
Noticed that last week.

$1400 in Ohio
&
$1500 in California

Black Friday get rich quick flippers ?
Just kidding guys - lol
Think both have been active in this thread.

One thing working against the roundport market right now is the manifolds have been back ordered for a pretty long time .
Just recently became aware of that.

Most Racers probably don't want As-Cast SM heads ,,,, or any SM head .

Small market on guinea pig heads I guess , shrunken more from those two factors.
Very fair prices offered , and no sales tax is another savings

Valve spring pockets appear cut for a 1.650" spring. The supplied PCE valves compared to some take out Edelbrock valve have more of an undercut stem than the Edelbrock valves.

Rocker stud helicoils did not have tabs popped off.Easy to do on intake as some hole there into the port,but the exhaust blind hols does not have enough room. it looks like Edelbrock guide plates will work.