[Skip Fix]

I still think to get these numbers out of an iron head is going to be hours of porting by someone who knows what they are doing and hope they do not hit water! New valves, seats,probably guides. And will have another 60lbs on the nose!

[Gach]

Skip good information, thinks for taking time doing this, although I’m not surprised at the results.

Pual K, the original AFR CNC Fulper heads, did have flow numbers. Jim Therttle ( (sp ) was they guy who paid for CNC program. The deal was, they needed a minimum of 3 sets. 3 of us bought into the program. Myself…Bob Maxey, and kid from Canada. Can’t remember his name. Maxey was WD with Edelbrock so we supplied casting and valves to Fulper. Anyway 8-9 months later I got first set out of three of us. Once I had my set checked it was discovered they were not CNC ported. I got on phone with AFR. They said they actually only did two sets in 2 year period. They offered me the program for $2500.00.

Anyway good information on SM heads at least guys now know what their getting into if they by a set, and expect to make good hp. Just have to asked yourself are they really worth the $1400.00 Black Friday sale.

[PAUL K]

Originally Posted by Gach

Skip good information, thinks for taking time doing this, although I’m not surprised at the results.

Pual K, the original AFR CNC Fulper heads, did have flow numbers. Jim Therttle ( (sp ) was they guy who paid for CNC program. The deal was, they needed a minimum of 3 sets. 3 of us bought into the program. Myself…Bob Maxey, and kid from Canada. Can’t remember his name. Maxey was WD with Edelbrock so we supplied casting and valves to Fulper. Anyway 8-9 months later I got first set out of three of us. Once I had my set checked it was discovered they were not CNC ported. I got on phone with AFR. They said they actually only did two sets in 2 year period. They offered me the program for $2500.00.



Anyway good information on SM heads at least guys now know what their getting into if they by a set, and expect to make good hp. Just have to asked yourself are they really worth the $1400.00 Black Friday sale.

Interesting Gach but if he didn't really sell AFR ported heads then he really didn't have flow numbers for them.... Lol

I always feel the heads should be judged at full price. At anytime they may decide to not run the sale..... Then one can decide what they are spending their money on. SM advertised them at XX amount retail.... Their quality should be based off that number. Imo

[Gach]

Originally Posted by Skip Fix

I still think to get these numbers out of an iron head is going to be hours of porting by someone who knows what they are doing and hope they do not hit water! New valves, seats,probably guides. And will have another 60lbs on the nose!

Exactly.. maybe 265-270 cfm that’s what best set of ported iron Ram IV heads I’ve had flowed. But your talking allot of port work. They were all done @.600 lift. But still they made 625 hp, but with lots of compression and .650 lift roller.

My thing is what SM are out of the box, and what you’d have to put into them to get to 625-650 hp if that’s what your looking for, but then again it could be done with pump gas. If a friend ask me to help him out with a set and his goal was 625-650 hp ( not that everyone is looking for that ) question is how much more money would we have to put into them. With framing out valve job and other things need done.

[X72GPX]

I was hoping for at least 600hp on pump gas with the CNC SM on a 461 cube. Can they be “fixed” to get 600 hp? Is it a better valve job and corrective porting? Who do you recommend to get them where they need to be?

Thank you!

[mgarblik]

I would think it would take a very aggressive camshaft and lots of compression to get there with 461 Cu Inches.

[Jay S]

Originally Posted by X72GPX

I was hoping for at least 600hp on pump gas with the CNC SM on a 461 cube. Can they be “fixed” to get 600 hp? Is it a better valve job and corrective porting? Who do you recommend to get them where they need to be?

Thank you!

Good valve job with wider angles into the bowl. Then my guess is it needs to have the short turn on the port pulled back. At that point it should be returned to a flow bench, and rechecked. I would continue to pull the short turn back until the turbulence is gone at the max lift of the cam that is going to be used.

The problem with the port work on this head is really not the lack of flow at the higher lifts. It is turbulence at those upper lifts. The turbulence ends up de-atomizing the fuel and sends raw gas into the cylinder. Trying to make big power using the flow where there is a lot of turbulence it will end up with raw unburnt fuel out the exhaust, which it needed to make more power. Most of the power was gained from the modest increase of flow from the CNC work was likely lost from the turbulence that was created from that work.

I think Paul K had the right idea, you would be better off starting with a stock set and doing pocket porting than this version of the CNC head. I am sure Skip won’t have any trouble getting the intake tract issues corrected .

Trying to live with the heads and make good power as they are, I think I would prefer a profile a pretty tight LSA, and or longer seat timing on the intake to help promote more scavenging. The heads appear to be lacking quite a bit of flow at low lifts and probably won’t scavenge all that well.. I also would would not get carried away with the cam lift very far into the area of lift that has the turbulence.

[Jay S]

I agree with Mike, It also need a lot of compression.

[Baron Von Zeppelin]

Originally Posted by Skip Fix

I still think to get these numbers out of an iron head is going to be hours of porting by someone who knows what they are doing and hope they do not hit water! New valves, seats,probably guides. And will have another 60lbs on the nose!

I didn't see this new flow bench thread until just now.
Thank you for all your time and effort Skip , and the same to your friend too.
Should be helpful to a lot of readers from here on out.

Curious question -
Which port did you flow ?
Either intake tract #2 or #3 (inner ports) was the one with the defect from the mold/core shift on all the heads ,
Is that the tract you flow tested ?

[Baron Von Zeppelin]

Originally Posted by mgarblik

...No idea what they charge for the CNC work..

Black Friday deal was $1400 for CNC with valves & springs
Year before it was $1100 As-Cast with valves & springs
So for those buyers , it was a $300 upgrade

Retail prices listed now - I think its an $800 jump to CNC
From the hip I'm thinking its $2200 pair & $3000 pair

I don't think As-Cast were offered for $1100 again this last time.
Just the CNC deal

[Skip Fix]

We tested only 1 port #2/7.

My buddy and I have been friends since the mid 80s. He worked as a mechanic and then at my old machinist's shop. they had a flow bench and a basic dyno back when a lot of folks were not using them. the old '"dial dyno" was set up to give good numbers that 'ran the number' at the track-unlike some of the otehr shops around with "generous dynos". Machinist ran NHRA stock with Pontiacs in the late 60s early 70s. Buddy got into building Harley's for a while and had a motorcycle dyno to check things out on porting, and EFI tuning . He has a nice '68 Charger 500" 383 with a Hilborn stack EFI run with a Holley controller and a OD trans that runs low 11s cruising with the A/C on to the track. picture of it was in the Caltrac catalog awhile back.

[Skip Fix]

Remember also LOTS of ported iron heads go into turbulence also. I see these as a step above what most folks would get from a "ported iron head".

[grivera]

Thanks for your work on this, Skip. By any chance do you have Edelbrock or KRE numbers on that same flow bench?

[Skip Fix]

Probably have some very ported high ports on it.

[Baron Von Zeppelin]

Originally Posted by Skip Fix

Remember also LOTS of ported iron heads go into turbulence also. I see these as a step above what most folks would get from a "ported iron head".

I agree , hands down.

Do you think you might see another 20cfm on the intake after you go over them a little by hand , and do your valve job to them ?

[Stan Weiss]

Originally Posted by Jay S

Good valve job with wider angles into the bowl. Then my guess is it needs to have the short turn on the port pulled back. At that point it should be returned to a flow bench, and rechecked. I would continue to pull the short turn back until the turbulence is gone at the max lift of the cam that is going to be used.

The problem with the port work on this head is really not the lack of flow at the higher lifts. It is turbulence at those upper lifts. The turbulence ends up de-atomizing the fuel and sends raw gas into the cylinder. Trying to make big power using the flow where there is a lot of turbulence it will end up with raw unburnt fuel out the exhaust, which it needed to make more power. Most of the power was gained from the modest increase of flow from the CNC work was likely lost from the turbulence that was created from that work.

I think Paul K had the right idea, you would be better off starting with a stock set and doing pocket porting than this version of the CNC head. I am sure Skip won’t have any trouble getting the intake tract issues corrected .

Trying to live with the heads and make good power as they are, I think I would prefer a profile a pretty tight LSA, and or longer seat timing on the intake to help promote more scavenging. The heads appear to be lacking quite a bit of flow at low lifts and probably won’t scavenge all that well.. I also would would not get carried away with the cam lift very far into the area of lift that has the turbulence.

My question would be has anyone sectioned a head or sonic checked a head to see if there is the needed metal thickness in the areas that need to be changed?

Stan

[Slick]

Originally Posted by Stan Weiss

My question would be has anyone sectioned a head or sonic checked a head to see if there is the needed metal thickness in the areas that need to be changed?

Stan

https://forums.maxperformanceinc.com...&postcount=105

https://forums.maxperformanceinc.com...&postcount=125

https://forums.maxperformanceinc.com...&postcount=126

Hope this helps,

Stuart

[Jay S]

Originally Posted by Skip Fix

Remember also LOTS of ported iron heads go into turbulence also. I see these as a step above what most folks would get from a "ported iron head".

There is a difference though between leveling out, and staying steady, or going turbulent and stalling, or even falling off. I obviously wasn’t there for the test, so I can only guess and look at pictures and results. Higher test pressure would likely make the turbulence show up earlier and make it worse where the turbulence is already prevalent. This tests was at 4”, so, what will happen at 8”, or 12”, or 28” test pressure? Probably won’t be good.

JMHO, this CNC version seems like a mess to run as is, if the plan was to just run a head out of the box, I would rather have an as cast set. My reasoning for that: the low lifts on these CNC’s flow pretty terrible (worse than the as cast set), the ports are to big for the flow, then they stall to early, with too small of a flow gain versus an as as cast set, and are showing turbulence WAY to early. But, if the fix is easy, and the plan is to put more work into the head anyway, (seems to be your plan Skip) maybe it could be a good value or a starting place.?? The exhaust side looks good. My feeling is work on the intake short turn will fix the early stall, but the low lift flows will still be bad, and will likely get even worse with short turn work. The low lifts might come back with a better valve job and some bowl work. To me the “value” of that CNC work would only be worth anything if the plan is to fix the issues, and that depends on what the corrections entail, and whether or not the port has room for those corrections. Pretty early yet to narrow any of that stuff up much.

[Baron Von Zeppelin]

Originally Posted by Baron Von Zeppelin

Retail prices listed now - I think its an $800 jump to CNC
From the hip I'm thinking its $2200 pair & $3000 pair

Some recent price adjustments -
Todays price online @ speedmaster79.com

CNC = $2500 pr
As-Cast = $2000 pr
Bare As-Cast = $1625 pr

Also - Special Sale was $1500 pr ($1491.00) for CNC
not $1400 pr
Special Sale As-Cast was approx $1200 pr

Short Summary to this point =
Since the heads are basic copies of a pre-existing commodity,
The CNC patterning was probably (almost certainly) digitized/copied from another sources product too.

From comments and pictures in the other CNC thread - they are left unfinished on the intake throats , bowls and pockets.
Has been strongly suggested the core shift probably limited those factors from complete tooling.

[Baron Von Zeppelin]

SM As-Cast
CNC
Ed Head


Intake
______SM. CnC. Ed
.200. 147. 139. 147.
.300. 213. 209. 206.
.400. 258. 269. 235.
.500. 269. 292. 259.
.600. 289. 302. 277.


Exhaust
______SM. CnC. Ed
.200. 124. 139. 115.
.300. 156. 162. 156.
.400. 177. 190. 178.
.500. 195. 209. 186.
.600. 202. 222. 197.


Yep