Desk Top Dyno

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Power output depends on the cylinder heads and there is rarely enough information for any computer program to get close. We use PipeMax and it can get close, but only if you know the VE. And nobody really knows the VE until after the engine is run on the dyno so that kind of makes the program useless for predicting power.

When you're dealing with something "weird" like W5 heads the best place to get a power estimate is from a W5 expert. And they most likely would want to know details on the heads before they gave you a number.

I can usually predict power within a few % just by looking at the parts a guy brings in to the dyno. But that trick only works for OOTB cylinder heads. Once someone starts whittling on the heads all bets are off. Power might go up but sometimes it goes down. Same thing with home ported manifold, home re-worked carbs, etc.

Good w5 heads with the right cam should be able to make 740 on that short block, but I'm not really familiar enough with W5 heads to predict a number. We just ran a 429 inch SB Chevy that made 780 hp on the dyno. So the question is if W5 heads are as good as a 15 degree SBC head. The 429 SBC had a much bigger cam than what you posted. I think the SBC was 280/290.
We plugged in a bigger Comp cam and it picked up 23 hp on the software. But we going to have Charlie Westcott grind us a custom design. But I do feel confident that in the end I'll be able to make 740 hp with it. But the proff will be in the ET when we get to that point. Thank you for all of your helpful replies.
 
I bet he will spread the cam out some from the 106 that was posted.
Alky and 14 + to 1
That cam that has been 140@3220 I think is 276/282 around 700 lift
Mine was 273/280, similar lift, on a 108, milder lobes.
Dwayne did both of them, that is who I would recommend for a cam, as he has done plenty of them, and they work.
 
The big problem with computer programs is that most of them use head flow data to predict power output. But Kaase, as well as others, have proven that head flow (as measured on current flow benches) doesn't equal power output. Kaase has some great discussions about how his Hemi heads make a lot more power than his wedge heads even though the wedge heads flow the same on the bench. A 400 cfm head can make 700 hp or it can make 900 hp. When that is true then the computer program can't make an estimate.

I witnessed this recently when we tested a GM 632 crate engine. The 632 has a hyd roller cam with beehive valve springs and it runs on pump gas. But the heads are so good that it makes over 1000 hp. The heads on the 632 are crazy, the ports are raised so high that you can see the intake valve thru the intake manifold. The GM 632 crate engine is basically a big pump gas shortblock with Pro Stock heads. The heads are so good that the engine can't help but make gobs of power.
 
Rumble has a set of W5’s that Brett ported years ago.

I wonder how much the DD numbers would change if you plugged in the flow numbers from that set of heads.

Numbers pilfered from Robb’s utoob channel:

IMG_3450.png
 
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Now to add to the confusion!!!!
Brett’s numbers on a 4.125 bore.
(WARNING - SO NOT RACE FLOW BENCHES!)

IMG_0438.jpeg
 
There we go again with a pathetic .300 number. He loves his 55 degree seat so I wouldn’t be surprised if it got one.
 
There we go again with a pathetic .300 number. He loves his 55 degree seat so I wouldn’t be surprised if it got one.
Again, what was it you got for the same number on the same head? Would you like to try to port a set? I’ll send them along.

:rofl:
 
What would you consider a good number at .300 ? Like 200 cfm ?

I strive for 200 min @ .300 but if the customer limits the head gasket (chamber size) I can’t do miracles. On the chamber limited set of 2.08 valve Edelbrock heads I’m doing right now I hit [email protected] but it took several trips on my bench to adjust a few things.
 
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I just say… I don’t port heads, I had Brett Miller port them.
You wanna make fun of the head and make disparaging remarks, talk to Brett and/or out port him.

Then I throw my hands up. No one but no one takes up the challenge and the **** talking stops.

The heads are what they are and that’s all they’ll be since the casting gave up the ghost.

Your J head flows better, well fuckin good for you and have fun with that. Sounds awesome and great. Since your an ace at J heads, perhaps you can teach Brett how to port. What do you want? Perhaps his phone number? You can call him up and brag.
 
I just say… I don’t port heads, I had Brett Miller port them.
You wanna make fun of the head and make disparaging remarks, talk to Brett and/or out port him.

Then I throw my hands up. No one but no one takes up the challenge and the **** talking stops.

The heads are what they are and that’s all they’ll be since the casting gave up the ghost.

Your J head flows better, well fuckin good for you and have fun with that. Sounds awesome and great. Since your an ace at J heads, perhaps you can teach Brett how to port. Would you like his phone number? You can call him up and brag.


I agree 100%. All these guys trashing Miller and not a one of them has built a 1000 horsepower small block.

Miller isn’t stupid. He uses steeper than 45 degree seats because they make horsepower, regardless of what a flow bench says.
 
Thanks man. It’s ******* hilarious how mutha F’ers start running their mouths against the head but never step up to the challange plate. Just slip away.

Don’t bother me with it. Ya’ll talk trash real fast against Brett’s work but run away like stink on the challenge to top him.

Killer6 can drive over and bragg to Brett.
 
I just say… I don’t port heads, I had Brett Miller port them.
You wanna make fun of the head and make disparaging remarks, talk to Brett and/or out port him.

Then I throw my hands up. No one but no one takes up the challenge and the **** talking stops.

The heads are what they are and that’s all they’ll be since the casting gave up the ghost.

Your J head flows better, well fuckin good for you and have fun with that. Sounds awesome and great. Since your an ace at J heads, perhaps you can teach Brett how to port. What do you want? Perhaps his phone number? You can call him up and brag.
Easy Dude, I'm not trashing anybody, those heads are not set up the same. PBR is probably correct about the valve seat angles, those sets of J heads I did 30yrs ago were only realizing ~.485" lift w/a 292°/.508" PurpleShaft using the T/A rockers, so I obviously focused on that lift range..they worked. You asked a question about expected flow @.300 when John said it was pathetic, I offered what I managed to do with the J's, that's all....I'm sure Brett can do J's as well as anybody can.......
Now go have a drink & admire one of Your tunnel ram setups already!!!!
 
I agree 100%. All these guys trashing Miller and not a one of them has built a 1000 horsepower small block.

Miller isn’t stupid. He uses steeper than 45 degree seats because they make horsepower, regardless of what a flow bench says.
Again, where did I "trash" anybody ...
I'm waiting....
 
I didn’t name anyone. If the shoe fits…
PBR made a comment,.....rumble quoted & addressed Me specifically, & You jumped in with "All these guys", unless You're counting John as more than one.........
 
So a guy building small block mopar engines at the highest level decides he wants to do his own version of a w5 head and guys on here think they can make more power with a ported stock/edelbrock/speedmaster lol. Have at it boys!, when you guys have engines that make power with non offset rocker heads like Brett has made then by all means enlighten us all!.
 
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PBR made a comment,.....rumble quoted & addressed Me specifically, & You jumped in with "All these guys", unless You're counting John as more than one.........


Do you know what “if the shoe fits” means?

If you weren’t bashing his work then the shoe doesn’t fit.
 
You asked a question about expected flow @.300

I did? Please quote it for me.

The rest you can go shove in Brett’s face. Brag to him.
All that you have said, I have said in the past about J/OEM heads.
 
Let’s get back to the dyno sim. If anybody runs the W5 numbers for Ha-Ha’s, post them up for entertainment purposes.
 
I did? Please quote it for me.

The rest you can go shove in Brett’s face. Brag to him.
All that you have said, I have said in the past about J/OEM heads.
You're right, You asked John what He thought His # would be on those particular heads at that lift, & 273 backed that up with the above quote. I simply shared My #'s, ......since there seems to be a half-off sale on train tickets to Triggerville, I'll leave so You can have some alone time...later.
 
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