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572 Hemi Camshaft Selection

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Okay, I need some opinions. I just got the block back from the machine shop. The combination is a 572 Hemi with late 90's Mopar heads that flow
Int - 411 @ .700 lift & 417 @ .800 lift
Exh - 222 @ .700 lift & 219 @ .800 lift
Yes the exhaust is pretty anemic. But I'm going to change heads right now....
I'm only going to be running 10.00's - 3600lb car spinning it 6800 - 4.56 gear, but will probably be going with a taller tire 30" now but will be going with 31".

I've called 3 different cam mfg. companies. In a lot of ways they all almost identical on the exhaust duration. They were a little different in Intake Duration and they were all different on lift.
CAM -1
Int. 800 lift - Exh. - 785 lift
int. 272 @.050 - Exh. 292 @.050
112 LSA

CAM -2
Int. 707 lift - Exh. - 733
int. [email protected] - Exh. - 292 @ .050
112 LSA

CAM - 3
Int. 768 lift - Exh. 750 lift
292 @ .050 - 296 @ .050
112 LSA

The cam I was running when it was a 498 and 512, was
800 int. - 785 exh.
[email protected] - [email protected]
This cam was picked out but one of our old engine builders. But at the time, the heads had not been flowed... that I know of.

The Cam Mfg. all were addressing the lack of exhaust flow with increasing the duration on the exhaust side.
My question is on the intake duration and the lift.

Any thoughts?
 
What LSA was the cam in the 498ci ?? Just wondering.
 
is that what most cam makers recommend for a stroker motor a wider LSA. I'm new to stroker motors.
 
Heck your heads have to flow better than my 572 wedge. The cam in mine is 285°/292°, .800"/.800" (.471" lobe) on 112 LCA. Shifted at 7000, traps 7200 with 31" 4.30 gear
Doug
 
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What’s the cr of the motor?

If the flow bench was the type that has the wall on the side away from you, like a SF-600, I’ve found that hemi heads will pick up a fair amount of flow by turning the head around(ex facing you) if you’re not testing with a flow tube.
And they also pick up pretty good with a flow tube attached.

An example:
Pre-Edelbrock MP hemi head, basic mild porting, 4.500 bore:
A- ex facing in
B- ex facing out
C- ex facing out w-2-1/8” flow tube

Lift——A——B——C
.500–219.5/236.6/267.7
.600–203.7/232.8/263.8
.700–201.7/231.6/261.9
.800–199.8/230.8/261.9

Looking through some notes, adding the 2-1/8” flow tube to a ported hemi head is worth 30-40cfm at the higher lifts.
 
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NOSTRT, I'm not sure.. two of the cam mfg. told me 110 - 112 and the third one was just 112. I'm thinking it has to do with the intake savaging the intake charge.

Doug, What heads are you running? Some of the Good Wedge Heads flow pretty dam well. But your cam and what they are suggesting is pretty damn close.

PR Heads... Thank you for the input... So you're saying to have the exhaust ports facing out, and flow tubes (are you talking about header primary tubes?)
I know he has a Super Flow Bench. I don't know if it's a 600 or not... I'm kind of thinking it is.
Looking at your numbers I'm not far off. And I notice that there is not much difference between 600 - 800 lift.

Oh yha... My Compression is going to be 12.8:1
 
My bench is a Saenz S-600, which is basically a copy of a SF-600.

On my bench, if I flow a hemi head with the exhaust facing away from me, then turn the head around so it’s facing towards me, the flow numbers go up.
Adding a flow tube, which is like a short piece of header on the head, the flow picks up quite a bit.
For me, the turning the head around really seems to be more of a hemi head thing, since I’ve tried it on some other heads and saw no real difference.

So, your 219cfm ex port might flow over 260 with a flow tube on it.

My point is....... that ex port might actually be a fair amount better than those numbers indicate.
Which might impact the cam decision.

I’d probably do something around .470-.480 lobe lift, 280/290-112.
 
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PR Heads - Thanks again for your insight, I really appreciate it.

I'm just wondering....What is the reason why turning the head around increases the flow numbers?

That's pretty interesting, your suggestion is on par with what Bullet had me with Duration 278 - 292 (sorry I typo'ed the original post)
And the Lift you suggested is real close to what Crane had me which is .480 - .478 at the lobe

I'll call the guy who flowed the heads and see how he did it. If he didn't turn them around, I see if they wouldn't mind put it back on and flowing it again with the head reversed.

Thanks again!

Kevin
 
Doug, What heads are you running? Some of the Good Wedge Heads flow pretty dam well. But your cam and what they are suggesting is pretty damn close.


The heads are Indy -1 with a 2.25 intake. I don't have an actual flow sheet. The were hand ported by Jeff Kobylski at Modern Cylinder Head 8-10 years ago. I bought them used. Compression is 15-1.
Doug
 
Depending on how the flow tube was shaped, if the tube would fit on the head with the head mounted with the ex facing away from you, I don’t think turning the head around would do anything.
On my S-600, it seems the proximity of the rear “wall” on the bench to the Hemi exhaust port, and the way the port is facing, blowing the air into the corner where the base and rear wall meet, seems to create a poor environment for the column of air to exit the head.
Turning the head around on that type of bench allows for the port to have unrestricted flow.
Not all benches are built this way. Many of them don’t have the “wall”, and on those there wouldn’t be any benefit to reversing the head.

FWIW, IMO......the hemi ex port in particular really needs to be tested with a flow tube if you really want a good handle on what it flows.

As always........ ymmv....... but I don’t bother testing the ex ports on hemi heads without turning them around anymore, and I test both with and without the tube.

As another example of how much influence the tube has on these heads....... ootb Ede Victor head, ex facing “out”, 4.500 bore.......
@.800 lift— 240.6 no tube, 273.1 with 2-1/8” tube.

Most of my flow tubes can be used with the exhaust facing “in”, but not the hemi one....... on that one the ex has to be facing out.

My cam suggestion is based on my assumption that if the head were tested with a 2-1/8” flow tube on it that it would be more like 250-260cfm....... maybe more.

Bullet is probably assuming that 219cfm is “the number”, and adding ex duration to compensate.
 
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Some benches have the wall...... some don’t......

2E517BE8-4359-4BD8-BA82-15B478701973.png 13ED0C5F-598C-4335-8D81-39F2CF0E6761.jpeg 6F6DA431-AFE9-4D51-8BCF-766223F7D790.jpeg
 
PRHeads, That's interesting stuff. His flow bench defiantly has a back wall.
Would the fact that the Hemi head is a lot wider be the reason the wall effects the flow (the wall increases turbulence).
It seems to me that the turbulence at the port exit has a huge effect on the flow numbers. By putting a tube on the head and moving the exit turbulence away from the port exit increases the flow.

Doug
Its funny, your cam and the cam I was running is pretty darn close. The old cam we ran when it was a 14.5:1 498, (same heads) - we had a Crane .500-.500 at the lobe / 284-286 @.050.
I would think if Jeff ported the heads they flow pretty darn good.

Thanks again both of you
 
Would the fact that the Hemi head is a lot wider be the reason the wall effects the flow

I think it’s the width of the head and the way the ex port aims down into the corner of the base and rear wall.
Whatever it is....... on hemi heads...... if I turn them around, the ex flows more.
 
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