Cam choice - matching the cam to the combo.....

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Rat Patrol

Rat Patrol

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If I have a 318/392 stroker, with heads that peak at 270cfm @ .600, 3600 stall and 3.91 gears -


I understand what duration is and how it effects the performance spread of a cam

I understand the effect of lift.

I am OK with the lift at valve vs head flow equation

What I don't get is this:

I have a Dyno 2003 Sim that tells me two cams - one makes more torque and slightly less peak HP - the other makes more epak HP at 500 rpm higher.

Trouble is:

- one does it between 2800 and 6200
- one does it between 3200 and 6800

One makes Peak HP at 5500, the other at 6000.

My converter will work fine with either - so how do I know which is best to pick?

PS - I don't want a "screamer" engine - its a street strip build but I don't want to leave HP on the table either.
 
Ill try to word this another way -

I'd estimate going though the traps at around 115 mph - 5500 RPM


1st cam;

HP TQ RPM
215 377 3000
331 434 4000
422 444 5000
446 426 5500
441 386 6000

2nd cam

HP TQ RPM

203 344 3000
319 418 4000
422 443 5000
449 429 5500
460 402 6000

Which should I use to get the best ET?
 
I need to know why if thats OK ? This is a learning exercise for me - is it that the torque is better through that range?
 
Not an expert, but if your trap RPM estimate is correct, cam #2 is not done building power, while #1 gives you the tq peak just prior and the HP peak right at, yor target RPM.
 
Those two cams are so close together, you're wasting time deciding. Just pick one.
 
I think those power ranges are off if this is you 4" stroke engine. But you already know that ;)
Another consideration for the #2 cam is less torque could be an advantage with limited tire and a tight convertor.
 
The stroke should have figured into the cams power range with the sim program.

I do agree that in some situations...the softer bottom end will be easier on crummy tires, but lets hope he's doing right.

Not to open a can of worms...but im sure there r many ways and hp rpm peaks we all have diff ideas about in obtaining the same result.

cam 1 with those gears and slicks along with the trap rpm is where im coming from in my recommendation, similar to what another member said a few posts up.
 
It's no problem Justin. Mal knows where I'm coming from and where my thoughts are. I've used cam 2 with some mild RPM heads (his are mild ported iron) and there's no loss oflow end. But it's a hydraulic roller, and there is no way, unless the car is pushed by a 9 second ride, that it's going to pull to 6800...lol. But I think the catalog does say it will.
 
Ok - thanks for the input - sounds like not an easy question to answer definitely.

Is Stroker Scamp right - are they so close it doesn't matter?

Moper knows that traction has been a struggle with the car having a very light back end on 255 Mickeys.

1Wild - The Howards does seem like a slightly better "fit"

The thing thats bugging me is i don't know which is better for my target HP of 450 and trap RPMs of 5500.


MRL - Here's the cam profiles and my best guess at head flow figures with my new J's.

Head flow -
Int Ex
.100 72 61.8
.200 135 118.0
.300 192 149.0
.400 230 164.0
.500 261 186.8
.600 270 194.6

Howards grind - LSA 110 ICL 106

Howards712105288_294.jpg


Crane grind - LSA is 112. ICL is 111

Crane699631.jpg
 
Wow, Crane is pretty proud of that cam, $440! The Howards cam will make more power all over the place. Take the $150 you saved from not getting the Crane and get a real nice set of 1.6 rockers and call it a day.

The Howards cam gets the Big nod from me.
 
Wow, Crane is pretty proud of that cam, $440! The Howards cam will make more power all over the place. Take the $150 you saved from not getting the Crane and get a real nice set of 1.6 rockers and call it a day.

The Howards cam gets the Big nod from me.
 
MRL - Can I ask why? Other than price I mean (and i agree with you - fierce gouging on the Crane pricing! :) )
 
They sure adjusted the pricing when they were sold... The last time I bought it the cost was $290.
 
Price is a factor here. Your NOT going to gain anyhting by spending $150 MORE for the Crane. Thats ridiculousness that they want that much for the cam.

But if you look at it this way, the Howards has more duration at .050", less at advertised. The lift is about the same. the more aggressive the cam, the more power it will make. the crane is lazy off the base circle, you dont want a lazy ramp. The Faster the valve can get open the better. This is why solid cams perform so much better.

if you really want the Best of both worlds, drivability and power, go with a solid roller. Killer bottom end, massive top end and everything in between.
 
OK - plenty of food for thought.

I've contacted Bullet- It'll be interesting to see what they come up with.
 
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