Andy, what brand/type of blow by meter are you using?

It is a B&B meter. Just an old analog type design with a ball in a tube. Not sure how accurate it is but it gives us some relative comparisons between engines. This 470 was reading around 5 cfm at WOT which seems to be in the ballpark for a performance engine.

My friend bought one from Jegs that's like what you described, and we couldn't get it to do anything except make the ball bounce. It's seems almost like the ball is too heavy, and it ends up sealing the tube until a bunch of pressure builds up, then it shoots way up, lets all the pressure off, then drops to the bottom and seals the hole again......then repeats that over and over.

Yes, it does bounce around a fair amount during a dyno pull. Best test for blow by would probably be a steady rpm or maybe a step test where the steps are long enough for things to stabilize.

In for numbers as well.

On the blow by meter when I worked at Katech, in Clinton Twp. Mi. We used one from "Dwyer " I Think the range was 0 - 10 CFM. Go to there web site, www.katech.com. They will show the dyno cell pictures,use that as a reference!!! Good luck!!

Local engine builder asked to see the heads then asked if he could hang onto 1 to see what numbers they'd get. He was impressed. I took a picture of their results.

When the results exceed the manufacturer's claimed flow #s, I question the flow bench's calibration.

Glad you said it so I didn't have to. Must be one of those Idaho brand benches.

Only passing on what they showed while doing other heads. They have nothing to gain no matter the results. If it's considered misinformation I'll gladly remove it.

I am a neighbor to R&R, and have had them do work, as well as know their reputation for performance matching their dyno results and flow tests.

This is why I don't count on flow numbers from other benches as being able to be directly compared to mine.
This isn't saying one bench or the other is more accurate than the other as much as pointing out that flow numbers gleaned from different sources can, and do differ.
I'm quite sure that the head tested at R&R and the one I tested would be much closer to each other than the two sets of numbers posted would indicate if they were tested on the same bench.
I mean, no one actually believes that two CNC ported heads are going to vary that much, right?

Do we know if the R&R test on the exhaust side is using a pipe or not?
And if so, what size?

On another topic, Andy.... Did you check the net lift with and without lash with the full sping load?
I'm wondering how much flex is in those rockers.

It isn't misinformation, it is just probably at the high end of the range for test results. Test setups vary and test results vary. Most engine guys understand that numbers vary from bench to bench.

I haven't done that yet but I will try to remember to next time I'm over at the dyno shop. We're planning to do some more carb and intake manifold testing the end of this week. I'd love to hit 700 hp with this combo but I'm guessing that I need a little bigger cam in order to see that number.

Torque peak right now is at 5700 with peak HP at 6300. Cam is 271/.460 lobe single pattern. We'll try a lash cycle and maybe retard the cam a couple of degrees to see which way to go for more power.

Whut?!

And dyno to dyno... and I've seen first hand some pretty big variation between a couple of dynos.

And DYNO to track. LOL.

Who uses the track as a measurement of performance?!

i dont get excited about flowbench or dyno numbers..MPH answers my questions