BB rpm heads

[metcoll]

Bought a set of rpm heads for my 440 and sent them to my engine builder, said he flowed them  @ 600 lift and they flowed 264...he hasn't started to port them yet..i thought these heads flowed 291 @ 600

[justcruisin]

That does seem low for what I have read, all castings don't flow the same, but 275-280 seems about normal. Still if you are having them ported by someone who knows what they are doing they should come out with the results others have achieved with them - depending on the level of porting and valve work. I have a set - OOTB, no problems in 6 years. Seen plenty of builds on a stock stroke 440 with OOTB rpm's around the 500hp mark.

[c00nhunterjoe]

How you set them up and how the bench is set will vary numbers. But the most important thing is the base number vs increase on a given bench. And more important then what they flow at .600, is what they flow at the lift your cam uses...

[Challenger340]

Bought a set of rpm heads for my 440 and sent them to my engine builder, said he flowed them  @ 600 lift and they flowed 264...he hasn't started to port them yet..i thought these heads flowed 291 @ 600

As mentioned it depends on the Bench and the Head as delivered.

That may be slightly low, but not far off.  
We've Flowed plenty of rpm's and never seen anywhere close to 291 @ .600".  

If I get time this afternoon I'll throw up a set of E-Street's(Brand new in the Box) which are advertised at the same Flow as the RPM's and get back here..... but most aren't much higher on our SuperFlow SF750 Bench than what your Shop saw.

For comparison, the Trick Flow Powerport 240 Heads we Flowed last week were BANG ON on our Bench versus Trick Flow's "published" Flow  numbers, like within +/-  zero to 2 cfm throughout the Lift range.

Maybe what I'll do is post our results OOTB for BOTH the PP240's and the EDDY E-Streets.

[metcoll]

That would be awesome thx

[68pplcharger]

 

[tan top]

 

[Challenger340]

I'm working on it.... just busier than a one-legged idiot at an ass-kicki'in contest

[BDF]

 

[Challenger340]

BB Mopar E Streets we Flowed today, OOTB, no changes.   They are advertised as the same-same "291" @ .600" as the rpm heads
Our Plexi Intake Radius seems to help some Heads, the NO Pipe "open" Exhaust hurts somewhat.

SuperFlow SF750 Bench
28"
Intake .500" Plexiglass Radius
Exhaust NO Pipe "open"

Lift       Intake     Exhaust
.100       59.5         55.0
.200     130.6        108.7
.300     193.4        147.8
.400     235.6        175.0
.500     261.2        190.9
.600     274.9        200.5


and for comparison purposes on our Bench, here are some Trick Flow PP240's from 3 weeks ago, which they Flow very close on our SF750 Bench ? to Trick Flows own published numbers ?
Again here, our Plexi Intake Radius seems to help, the "open" Exhaust hurts.
28"
Plexiglass .500" Radius Inlet
NO Pipe "open" Exhaust

Lift         Intake     Exhaust
.100         74.0        55.5
.200       154.6      125.2
.300       227.8      168.3
.400       283.0      191.5
.500       313.2      209.7
.600       329.1      225.9
.700       335.5      232.2

[RECHRGD]

About ten years ago I bought a set of the Mopar aluminum '452' heads and sent them off to Dwayne Porter for prep and stage one porting.  These heads are basically the same as the RPM heads with straight plugs.  Dwayne said that they had some core shift to deal with and that took most of his alotted time.  So little more than a cleanup was done.  They flowed as follows....

              Intake.                  Exhaust     
0.100.      69.4.                       57.0
0.200.     151.8.                     112.0
0.300.     219.5.                     143.5
0.400.     256.1.                     170.7
0.500.     273.8.                     191.1
0.600.     283.8.                     205.5

[BSB67]

BB Mopar E Streets we Flowed today, OOTB, no changes.   They are advertised as the same-same "291" @ .600" as the rpm heads
Our Plexi Intake Radius seems to help some Heads, the NO Pipe "open" Exhaust hurts somewhat.

SuperFlow SF750 Bench
28"
Intake .500" Plexiglass Radius
Exhaust NO Pipe "open"

Lift       Intake     Exhaust
.100       59.5         55.0
.200     130.6        108.7
.300     193.4        147.8
.400     235.6        175.0
.500     261.2        190.9
.600     274.9        200.5


and for comparison purposes on our Bench, here are some Trick Flow PP240's from 3 weeks ago, which they Flow very close on our SF750 Bench ? to Trick Flows own published numbers ?
Again here, our Plexi Intake Radius seems to help, the "open" Exhaust hurts.
28"
Plexiglass .500" Radius Inlet
NO Pipe "open" Exhaust

Lift         Intake     Exhaust
.100         74.0        55.5
.200       154.6      125.2
.300       227.8      168.3
.400       283.0      191.5
.500       313.2      209.7
.600       329.1      225.9
.700       335.5      232.2

Really like the low lift numbers on the TF too.   Bob, how much do you think the low lift numbers would change with your performance valve grind?

Thanks for posting

[RECHRGD]

I remember someone stating that the horsepower potential of heads are equal to twice the intake flow.  Is that a general rule of thumb?

[c00nhunterjoe]

Cfm x .257 was the formula that is used by many but it is not a good rule in my opinion. Take a stock head and put it on a very healthy 500" stroker short block and it will blow that formula and doubling the cfm theory off the chart.

[PRH]

Flow @28" x .257 is the estimated power potential for one cylinder.

Example: 300cfm x .257 = 77.1
77.1 x 8 = 616.8hp

If your hp goals are higher than what the numbers come out to, it generally means you'll have to work a bit harder to achieve the desired results.

The last set of each of these I tested ootb @.600 lift:

TFS 240 - 325/218
E street -  286/192
Stealth -  256/184

All on 4.375 bore, 28", radius plate, no tube on ex

[68pplcharger]

Flow @28" x .257 is the estimated power potential for one cylinder.

Example: 300cfm x .257 = 77.1
77.1 x 8 = 616.8hp

If your hp goals are higher than what the numbers come out to, it generally means you'll have to work a bit harder to achieve the desired results.

The last set of each of these I tested ootb @.600 lift:

TFS 240 - 325/218
E street -  286/192
Stealth -  256/184

All on 4.375 bore, 28", radius plate, no tube on ex

My Uncle has a 451 CID (400 bored and stroked) with RPM heads OOTB and it put out 585hp on the dyno. formula seems pretty close to me for potential.

[Derwud]

I haven't even got my 540 running yet and I want to throw the Stealth Heads away and get some TF's...

[Challenger340]

BB Mopar E Streets we Flowed today, OOTB, no changes.   They are advertised as the same-same "291" @ .600" as the rpm heads
Our Plexi Intake Radius seems to help some Heads, the NO Pipe "open" Exhaust hurts somewhat.

SuperFlow SF750 Bench
28"
Intake .500" Plexiglass Radius
Exhaust NO Pipe "open"

Lift       Intake     Exhaust
.100       59.5         55.0
.200     130.6        108.7
.300     193.4        147.8
.400     235.6        175.0
.500     261.2        190.9
.600     274.9        200.5


and for comparison purposes on our Bench, here are some Trick Flow PP240's from 3 weeks ago, which they Flow very close on our SF750 Bench ? to Trick Flows own published numbers ?
Again here, our Plexi Intake Radius seems to help, the "open" Exhaust hurts.
28"
Plexiglass .500" Radius Inlet
NO Pipe "open" Exhaust

Lift         Intake     Exhaust
.100         74.0        55.5
.200       154.6      125.2
.300       227.8      168.3
.400       283.0      191.5
.500       313.2      209.7
.600       329.1      225.9
.700       335.5      232.2

Really like the low lift numbers on the TF too.   Bob, how much do you think the low lift numbers would change with your performance valve grind?

Thanks for posting

In the past, we farted around with some grinds to get fatter lower on some of the legacy heads(stealth etc) and had some success... I mean we can grind seats & widths at any angles we want right ?

But applying on the TF240's ?
I have No Clue !
mainly because thus far.... and after Flowing the TF240's we've brought in for Customers.... I can't see any reason to try, and I would be afraid to frig up what is a pretty darn good Head OOTB ?

[Challenger340]

I remember someone stating that the horsepower potential of heads are equal to twice the intake flow.  Is that a general rule of thumb?

Lots more going on.... but IMO, as a general "rule of thumb" just for initial planning purposes it's relevant for DIY guys.

It CAN be exceeded...
As a favour for a friend, just last week we ReMachined/ReBuilt(new Pistons) & Dyno'd a very well used up bunch of old 509 Bowtie Parts using OOTB Dart Pro1's that Toileted and went down much past .625" Lift @ 365 cfm(the guy did NOT want the Heads fixed so we just re-guided & Valve/Seat grind).... we still hit 785 hp by 6800 rpm with a .722" Lunati.

[BDF]

Thank you al for the information, it is very interesting to me.

[justcruisin]

Great info,  do the heads come out at 78cc's for the PP240's as delivered.

[Kern Dog]

I haven't even got my 540 running yet and I want to throw the Stealth Heads away and get some TF's...

I have ported Edelbrocks and feel the same way!
The 70 Charger hood makes intake manifold selection somewhat limited. I wonder what intakes work with these heads without causing clearance troubles.

[PRH]

I wonder what intakes work with these heads without causing clearance troubles

The same intakes that fit stock heads, Stealths, RPM's....... the TF240's have non-raised std sized ports.