906, Edelbrock RPM, Standard Stealth

[heyoldguy]

It's been an interesting two weeks on the flow bench.

We have been wondering just what you could get out of the 906, Stealth and RPM with the standard stock port window. Turns out they all seem to be capable of about the same peak flows @ .700" lift. RPM 335 cfm, Stealth 337 cfm & 906 338 cfm. By raising the port opening in another port, the flows went to 346 cfm with the Stealth and 350 cfm with the RPM. Haven't put the 906 to the bigger port test in this session.

It doesn't make sense to push these heads to those flows when other heads can do the same or better with less work, but it was fun experimenting just to see what they could possibly do.

Strange to think of it though, you could buy a pair of Stealth heads, spent the money for valves and porting, and have a head that flows as good as a ported B1 BS, for less money.

[Ghoste]

That is interesting.  Are you planning to take the 906 to that next test with the bigger port?

[heyoldguy]

Not with the 906 heads being used in this session. Previously they have gone 339-342 cfm @ .700" and only once to 349 cfm.

[Ghoste]

And flow for them is well documented anyway I suppose.  The realy interesting thing is your point about the Stealth and the B1 BS.

[tan top]

  couple of years ago was about to get a pair of stealths ,

would rather iron  over aluminum heads ,   but just thinking spending big money getting them worked with all the tricks  ,   flowed .  on a 40 plus year old part  , that it is not uncomon for them to crack even when stock , factor in grinding on the ports etcetc , what might happen after a few hundred heat cycles   

saying this would love to get a pair of muscle motors 906 CNC  heads !! that can support over 600 horse

[heyoldguy]

  couple of years ago was about to get a pair of stealths ,

would rather iron  over aluminum heads ,   but just thinking spending big money getting them worked with all the tricks  ,   flowed .  on a 40 plus year old part  , that it is not uncomon for them to crack even when stock , factor in grinding on the ports etcetc , what might happen after a few hundred heat cycles   

saying this would love to get a pair of muscle motors 906 CNC  heads !! that can support over 600 horse

Well, I know what happens to our 906 heads when Comp Cams forgets to turn the water on to the engine before the dyno test. We repair the guides, put the scrapped engine back together and make 730 HP.

[tan top]

 couple of years ago was about to get a pair of stealths ,

would rather iron  over aluminum heads ,   but just thinking spending big money getting them worked with all the tricks  ,   flowed .  on a 40 plus year old part  , that it is not uncomon for them to crack even when stock , factor in grinding on the ports etcetc , what might happen after a few hundred heat cycles    

saying this would love to get a pair of muscle motors 906 CNC  heads !! that can support over 600 horse

Well, I know what happens to our 906 heads when Comp Cams forgets to turn the water on to the engine before the dyno test. We repair the guides, put the scrapped engine back together and make 730 HP.

yeah i remember reading about what happened there  ,  was it as much as that i forget , 730 , thats real good numbers

http://musclemotorsracing.com/muscle-mike-blog.html

[Chryco Psycho]

That would make sense then , I ported a set of 452 heads & we swapped to the Eddy RPM heads also ported & gained 3 hp

[heyoldguy]

Yep, if you put 2.14/1.81 valves in a 452 head you can beat the pants off a mildly ported RPM Performer head.

[Budnicks]

Thanks HeyOldGuy, great info...

[heyoldguy]

Yep, if you put 2.14/1.81 valves in a 452 head you can beat the pants off a mildly ported RPM Performer head.

Oh,oh. I forgot to say that you also need to port them 452 heads along with installing the valves.

[Chryco Psycho]

It does seem to help doing some port work on the Iron heads 

[firefighter3931]

Any "before" vs after flow numbers ? Just curious what an untouched port flows on your bench 



Ron

[cdr]

heyoldguy,very good #s,would like to see what you could get out of the super stealth heads,i havent had time to get back to work on mine but will let you know  thanx charlie keel

[heyoldguy]

Any "before" vs after flow numbers ? Just curious what an untouched port flows on your bench 



Ron

No problem. It'll be later tonight, I'm just on a quick break.

[heyoldguy]

Ah, to answer stock flows of the Stealth and the RPM heads with comparisons to ported heads. I figured as long as we were doing this comparison I'd kick it as high as I could. I'm now all out of ports to work in my test heads.

First the Stealth

............Stock......Past Ported.......Today

.100".......67............73...............71
.200"......142...........149.............153
.300"......205...........214.............217
.400"......240...........256.............265
.500"......255...........288.............301
.550"........................................325
.600"......267...........304.............331
.650"........................................339
.700"......268...........322.............344
.750"........................................348


And then Edelbrock RPM

............Stock.........Stock.........Past ported..........Today

.100"........70.............71...................73..................75
.200".......143...........155..................148................152
.300".......201...........205..................213................216
.400".......243...........252..................258................265
.500".......271...........275..................289................301
.550"..................................................................322
.600".......285...........286..................305................333
.650"..................................................................343
.700".......293...........287..................321................350
.750"..................................................................354

I sacrificed some lower lift flows today, just to see how high I could push it in the .550"-.750" lift range.

[tan top]

    stealth real good at 550  & 600 lift   not going too radical with cam lift

[Budnicks]

Thanks HeyOldGuy that's allot of work.... I appreciate it, great comparison...

[Musicman]

Good work brother

There's nothing more valuable than quality information... Especially when it comes in the form of a good old fashioned Side by Side comparison.

[Challenger340]

Good for you Oldguy  ....and thx for sharing the comparisons, interesting stuff.

From my memories back in the day, it takes an awefull lotta work...and TIME... to get iron stuff up around 330-340 on any Bench !
Thats as far as we ever got without pokin holes !

[heyoldguy]

Yeah, my favorite place to install holes is in the water jacket, between the intake bowls, just by the head bolt hole. Or in the heel of the bowl between the valve guide and the seat.

[Budnicks]

Challenger340 those are some damn perty looking cast iron heads, intake ports there...

[Musicman]

Farg'n magnificent 

[firefighter3931]

Any "before" vs after flow numbers ? Just curious what an untouched port flows on your bench 



Ron

No problem. It'll be later tonight, I'm just on a quick break.

Thanks for posting the comparisons....outstanding results ! 



Ron

[ChargerST]

Those are some decent numbers! is there a reason anymore for choosing RPMs over Stealths when you're gonna get them ported anyways?
So do you offer porting work or was this just for fun?