Stealth, RPM, 906 heads

-
I'm now out of ports to test grind in my only RPM head I have on the shelf.

Today's results.

.............Stock.........Ported

.100"........71..............75
.200".......155.............152
.300".......205.............216
.400".......252.............265
.500".......275.............301
.550"........................322
.600".......286.............333
.650"........................343
.700".......287.............350
.750.........................354

It's kinda like we thought, the Stealth and the RPM are pretty equal and bettern anybody figured.

I think I have pushed it far enough and had better get back to the real work.
 
IQ52 said:
It's kinda like we thought, the Stealth and the RPM are pretty equal and bettern anybody figured.
Click to expand...

They should be, the stealth is a copy of the RPM .
 
Ok Jim, lookin good. How about the rest of the story........... The exhaust side of things!

SO 330-340 at .600-.650" is very doable on the RPM head. Good stuff. Now I have a question, what is the port volume on this type of port(the cc's)?
 
I'll try, there are other priorities at the moment.
 
I know your super busy, I talked to Dale the other day. He told me you were swamped with work right now.

I just wanted to keep this thread going, its good stuff and is helping a lot of guys out with the choices they make in heads.

The info you provide Jim is invaluable, and worth waiting for.

Ya know, your only about 350miles from where my parents live in MT. Just love the High Country.
 
So while testing the EZ exhaust, we drug out the Edelbrock Performer RPM head and tested the exhaust on that head.

1st column, RPM box stock flows as listed by Edelbrock. 2nd column, box stock as tested w/o tube. 3rd column, box stock as tested with 2" tube. 4th column, ported and tested w/ 2" tube.


.100"......70.......59.......61......65
.200".....126.....108.....117.....151
.300".....160.....151.....165.....192
.400".....188.....176.....198.....229
.500".....206.....190.....221.....253
.600".....217.....197.....234.....271
.700".....223.....203.....243.....283

There wasn't any time to do anything other than one quick exhaust port, I've got to finish the EZ heads.
 
MRL Performance said:
Ok Jim, lookin good. How about the rest of the story........... The exhaust side of things!

SO 330-340 at .600-.650" is very doable on the RPM head. Good stuff. Now I have a question, what is the port volume on this type of port(the cc's)?
Click to expand...

The port volume on the RPM head flowing 350cfm @ .700" lift turned out to be 258cc.
 
MRL Performance said:
WOW, I want some of those! Thats great flow out of a port that size.
Click to expand...

How's about the Stage VI ports I measured this morning? 341 & 346cfm @ .600" with 243 and 244cc port volume. We've just barely started playing with these heads.
 
No. But...............

In talking with Edelbrock Tech yesterday, The 452 head is made by Edelbrock and is the same as the RPM head, except for the 452 having a straight spark plug placement and the RPM having an angled plug.

So, that being the case, all the information on the RPM would be the same for the 452.

Please, anyone knowing different, correct me quickly!
 
Wa-da-ya-say we throw in some flows from different small heads with standard offset rockers and include their port volumes, okay? The RPM, Stealth and Stage VI.

........228cc VI...234cc Stealth...244cc VI...249cc Stealth....259cc RPM

.100".....85.............77.................75...............73.................84
.200"....157............153...............150.............152................158
.300"....214............216...............215.............218................215
.400"....261............265...............267.............267................252
.500"....299............306...............311.............308................299
.600"....313............324...............341.............336................328
.700"....333............337...............346.............346................341

So what? Well the Stage VI and the Stealth flows are tests we just recently produced in our first serious studies of those heads. The RPM results are flows from years ago, but, we have dyno results from those heads. If you look at the top of page 2 here, you can see the most recent results of our RPM tests.

What kind of power can one get from the flow results in the table above? The only one I can say for sure are the RPM flows. We made run after run, well more than twenty, at 770 HP to 787 HP from an 11.7:1 CR, RPM headed, single 4bbl, 451ci stroker.

It is well known that there are other aftermarket aluminum heads that can make that kind of horsepower or more. Are there any of them that can make that power WITHOUT BEING PORTED? What I'm saying here is, you may not have to buy another more expensive head, and then have it ported, if you are staying under or around 750 HP and you already have the Stage VI, Stealth or RPM. Port them, they can do it, I've seen it.

Oh my, we need big volume because Indy says so! Oh really? Or is it because nobody could deliver decent flows at lower volumes.

If you don't have your heads yet and you're shooting for big power now or someday, get the big Indy, Brodix, Victors or whatever.

Please, if I'm wrong point me to the tests so I can read them. I've had enough of people saying, "Ya gotta have.......!", without the evidence to back it up.
 
IQ52 said:
Wa-da-ya-say we throw in some flows from different small heads with standard offset rockers and include their port volumes, okay? The RPM, Stealth and Stage VI.

........228cc VI...234cc Stealth...244cc VI...249cc Stealth....259cc RPM

.100".....85.............77.................75...............73.................84
.200"....157............153...............150.............152................158
.300"....214............216...............215.............218................215
.400"....261............265...............267.............267................252
.500"....299............306...............311.............308................299
.600"....313............324...............341.............336................328
.700"....333............337...............346.............346................341
Click to expand...


What is the difference and part numbers to the Stage VI heads?

It is a shame there a bit pricey.
 
Salty Dog said:
What is the difference and part numbers to the Stage VI heads?

It is a shame there a bit pricey.
Click to expand...

Those are two different ports we ported, side by side in the same standard port head, part number P4529335.
 
Yeah we do. Samples? OK.

................318/675 casting..........J head............RHS LAX......RHS 1.94

.100"................63.........................78.................78..............77
.200"...............124.......................139................147............143
.300"...............177.......................187................203............194
.400"...............218.......................232................241............234
.500"...............255.......................270................275............260
.600"...............272.......................292................296............278
.650"...............277
.700"...........................................298................306............288
 
You must log in or register to reply here.
-

Back
Top