Shelby FE Aluminum Heads

[cjshaker]

Everybody is fixated on small ports that flow a lot right now.  i.e. high velocity.   Is there ever any advantage to a bigger slower velocity port?

pl

Check out Jays response in his "FE Power Cylinder Heads - More Test Results" thread (response #42), which is a reply to the video that Barry posted. If there's one thing that's certain, it's that there are no 'definites" when it comes to engine building. It all depends on combination. The only 'certain' that I know of is that experience rules.

[plovett]

This is copied from the Stan Weiss website.   The info is not too detailed.   I'm assuming this is from the old style Shelby heads.  Just FYI.

Manufact.
Part Number                      
                                                Port/Vol    Valve Size Int/Exh   Comb. Cham. Vol     .400         .500         .600            .700   
Shelby 427 Alum                           N/A             2.25/1.75                   N/A             241/156   264/175   275/180      279/-
Shelby 427 Alum Stage II Porting   N/A             2.25/1.75                   N/A             265/185   294/200   309/209      314/214      
Shelby 427 Alum                         163/128        2.25/1.75                    82                                             280/185   
Shelby 427 Alum Stage II Porting   N/A                                               82                                             320/235   

[chilly460]

The website actually says 310 cfm.  Not a big difference, but that is pretty good flow.  On the other hand, I'll be my ported Edelbrocks flow more than that when I put big valves in them.

Everybody is fixated on small ports that flow a lot right now.  i.e. high velocity.   Is there ever any advantage to a bigger slower velocity port?

pl

Interesting question, would a 300cfm say 205cc head ever make more power than say a 330cfm 170cc head, or would it only make as much if the big head flowed the same?  Guessing it may make more peak but in the car it would actually slow down. 

[frnkeore]

It seems to me that a high velocity head, would give a wider power band (higher average HP) than a low velocity head, especially in wet flow.

[blykins]

There will always be a compromise when it comes to "universal" heads.

A large port will feed a large engine but will be sluggish on a small engine (unless it's high rpm application). 

A small port will be zippy on a small engine and may feed a large engine up to a certain point and then the head needs more volume to meet the demands.

Choosing the cylinder head for the application is what's necessary.  Unfortunately, there are sometimes situations that are dictated by circumstances. 

[Tommy-T]

This is copied from the Stan Weiss website.   The info is not too detailed.   I'm assuming this is from the old style Shelby heads.  Just FYI.

Manufact.
Part Number                      
                                                Port/Vol    Valve Size Int/Exh   Comb. Cham. Vol     .400         .500         .600            .700   
Shelby 427 Alum                           N/A             2.25/1.75                   N/A             241/156   264/175   275/180      279/-
Shelby 427 Alum Stage II Porting   N/A             2.25/1.75                   N/A             265/185   294/200   309/209      314/214      
Shelby 427 Alum                         163/128        2.25/1.75                    82                                             280/185   
Shelby 427 Alum Stage II Porting   N/A                                               82                                             320/235

Those numbers look pretty accurate from the Stage II Shelby heads I have.

They are cast by Arias. They are a quality part with slight improvements from the Ford Medium Riser head but still used the Ford chamber.
I got these heads because they were torched out between 7&8. They have since been repaired and are ready to rock 'n roll once more.

[plovett]

Everybody is fixated on small ports that flow a lot right now.  i.e. high velocity.   Is there ever any advantage to a bigger slower velocity port?

pl

Check out Jays response in his "FE Power Cylinder Heads - More Test Results" thread (response #42), which is a reply to the video that Barry posted. If there's one thing that's certain, it's that there are no 'definites" when it comes to engine building. It all depends on combination. The only 'certain' that I know of is that experience rules.

Excellent video!  I should have watched it when Barry posted it.  Thanks for reminding me.  Going to have to re-watch it a couple of times and digest it.

pl

[plovett]

Those numbers look pretty accurate from the Stage II Shelby heads I have.

They are cast by Arias. They are a quality part with slight improvements from the Ford Medium Riser head but still used the Ford chamber.
I got these heads because they were torched out between 7&8. They have since been repaired and are ready to rock 'n roll once more.

Hooray for the repair-ability of aluminum.   I imagine those heads will rock 'n roll. 

pl

[plovett]

Everybody is fixated on small ports that flow a lot right now.  i.e. high velocity.   Is there ever any advantage to a bigger slower velocity port?

pl

Check out Jays response in his "FE Power Cylinder Heads - More Test Results" thread (response #42), which is a reply to the video that Barry posted. If there's one thing that's certain, it's that there are no 'definites" when it comes to engine building. It all depends on combination. The only 'certain' that I know of is that experience rules.

The first thing that is interesting to me is how he says velocity affects the short turn radius.  My first thought is that a slower speed there would help air and especially fuel make the turn, but apparently that is not the case.   A higher velocity reduces pressure there and "pulls" air and fuel around the corner.   That is, at least at first, anti-intuitive to me.  Then I think of a carburetor venturi  speeding up the air (and dropping the pressure) and it makes sense. 

edit:  Here is Barry's link to Darin Morgan's video from the other thread that Doug mentioned and Jay replied to.  whew!

https://www.youtube.com/watch?fbclid=IwAR01CNJWFTT09GrC8SfClQTDHhQcq5lN07vf2ZJaVEIG0jehKcGhOXiZqrs&v=qhsTQn0uUOQ&feature=youtu.be

[preaction]

I purchased a set of their stage 2 MR heads and after getting them  to my engine builder we had them checked  for flow and they didnt reach the non ported spects, they took them back stating nobody ever checks them.

[plovett]

I purchased a set of their stage 2 MR heads and after getting them  to my engine builder we had the checked for for flow and they didnt reach the non ported spects, they took them back stating nobody ever checks them.

What did yours flow?

pl