572-13 head flow-by flow tech 2

Larry Smith of flow tech 2 did these beautiful ports. I know little about all the ins and outs of what makes power, but trust Todd of Marsh Performance to steer me in the right direction. The numbers came back, and look good to me. If you compare them to the 440-1 numbers , looks very promising. I run a . 848 net lift cam for help in comparison. The jesel gear arrived, pistons are supposed to arrive tomorrow.

It will be interesting to see how they stack up on the other flowbench.

it will for sure. Since you port heads, a little info on valve angles. No back cut on either intake or exhaust. I was told a back cut brought up the flow up to . 100, but a net loss occurred in the midrange. So i was told don't let anyone change that.

I went to a two day theory only class on head porting years ago and Darren Morgan recommended putting a 30 degree back cut on everything and his reasoning was it will never hurt and usually help. Like I said that was years ago so that thinking may have changed. He has some really good videos on YouTube that I have shared and guys really enjoy them. I have never watched them because by now I know how I want to go about it and after 100’s of flow tests Im kinda set in my ways. I prefer to do it at least on the intake valves. The 30-45 minutes that he spent on the exhaust side was worth the 600.00 plus the 300.00 I spent to take my son.

Here is a pic of the valves. Maybe it is unique to these ports? I am not into head porting other than paying for it. So it is mostly a mystery to me.

Greg
What you said is exactly what happened here. Larry did a flow test with back cut valves, (ones I had) and found exactly that. Small gain down low but gives it all back in the mid range. NOT saying that would happen with every valve and port combo but on these that is what happened so hence no backcut. Todd
He will talk to you about anything you have questions about or I will try to answer them.

Thanks Todd. I think about a similar situation where 30 degree seats work well in some situations, like pontiacs. But mopars and others do well with 45 degree seats, and some high rpm high duration combos want steeper seat angles. It all goes to show that there are no tried and true rules, just trends.

The work looks great to me. I have no idea how the engine will run but the parts look super nice.

The porting looks top-notch to me. I also agree with not back cutting intake OR exhaust valves. On the heads I do, it helps at low lifts but hurts high lifts, the exact opposite of what you want. The only time it might be beneficial is with stock lift camshafts when you need the flow any way you can get it.

Larry Smith was a head porter at Penske Racing for many years??

i know he was working for a nascar team, can't recall who.

Yes it was Penske South. The cup shop. He has also ported probably close to a hundred sets of Indy heads for me and I cannot count how many others. Todd

Nice stuff Greg.

R&R flow numbers. Top numbers are from my 440-1 heads, R&Rs bench. Two ports tested,note differences.

I guess that shows you a back cut valve is the way to go.

Looks to me like pretty substantial gains from the back cut thru .700 lift.

The crossover point is probably around .750” lift.

I agree, it LOOKS like the back cut is the way to go, but look at the duration at various lifts with the cam i have. My guess is a cam of .800
net lift like Indy suggests might do well with a back cut? No back cut, 205 and 213 duration at .200 lobe lift, gross lift .868 might fair better
Since the port stalls before .700 lift. Only way to tell is run it, swap to back cut valves after getting a baseline.
The duration at valve lifts is net, after lash is accounted for.

I wonder how much actual CFM flows through the motor at or below 3/4 max lift

that works out to about half the valve event, time wise. Another question to ponder- if a port goes turbulent, does the turbulance continue as the valve starts to close, causing a net loss of potential cylinder fill at lower lifts, end of the induction cycle? Makes me think of a cattle stampede heading for a narrow gate,,,,,,, it may not end well!

Very nice hardware, Greg! Can’t wait to hear the results when the time slip prints! It’s gonna ride for sure LOL!

A good 1D simulation like EngMod4T will show you that plus so much more. Buying Ricardo WAVE or GT-POWER might be slightly more accurate(you can plug in different burn models more easily) but unless an engine OEM are simply too expensive.

A curious person can learn more about ICEs in a few months with 1D software than a lifetime of learning via other means. It just requires careful measurements that most enthusiasts don't seem willing to collect.

It would be interesting to see what some of the better modeling software would spit out for Gregs build with the two different flow curves plugged in.

Yes it would, I'm gonna say it would like the back cut on the intake only, just my opinion

If Greg had the data to plug into EngMod4T I would run a few scenarios, but in order to to do so - and get something of value for outputs - requires hundreds of measurements; some of which aren't simple to obtain.

For a quick and dirty analysis of the two flow curves, Engine Analyzer Pro(free trial period) might price interesting. I'd do it, but I have wasted the trials on all my PCs and cannot locate the pertinent files and delete, restoring my boxes to the pre-trial state.

Generally, the best way to gage a good cylinder head for a novice is to see if it performs on the engine. You've been lucky to have access to some good people in this build. (Larry and Todd etc) If the car doesnt run to your expectations probably the last thing I'd examine is the heads or intake. Just the same, we appreciate you sharing the pieces and some data you have on them!

Get that thing screwed together and in the car already

YaaaaaA. Winters coming. Lol 😂

So true. Well, the crank came back, offset ground to 4.560 (yes, 4.560!)which fits the expensive pistons i bought for the -13 heads and a set of poweradder + Molnar rods that are 7.0 long. Makes 580 cubes at 4.50 bore. So i wait for the crank to get balanced and pistons and rods to get pin fitted. Then i can put it all together and hopefully dyno it to dial in the fuel curve. Maybe race at BIR mid september!

I also sat in a seminar by Morgan and I usually back cut all the intake valves. The way i have found that gives the best results is to grind the seats and then slap the valve in the head to get a mark where the valve will seat, then grind the back cut angle so you come close to the seat mark. I want the face of the valve to be at least .060 wide, so if perfect .030 on each side of the seat mark you got slapping the valve. If you just grind a 30 degree back cut on the valve and it is too far away from the seat area it does not give good results. I think you posted on speed talk as well. But you need to check the short side air velocity, if you increased the flow with a back cut you may increased the velocity to make the short side unstable at high lifts, I think Morgan talks a lot about velocity in the ports as well. I have found just a little work with a sanding burr will fix most issues like you describe.

When working on motors and using "theory" please remember the valves open and close interrupting the air flow on both intake and exhaust sides.
My message is a flow bench doesn't do that so make sure you have before and after data from either an engine or chassis dyno or from the track with very similar weather conditions when testing before and after ALL changes
I remember meeting Jacko, an early SO CA very good head porter, in 1969. He had some aluminum 426 hemi heads he was working on for Mopars Direct Connection parts R&D department, he didn't have a flow bench and said he could see what the air would do under vacuum or pressure on the exhaust side.
I'm sure he used a big commercial vacuum cleaner with a smoke tipped sparkler on the intake side and would reverse the hose on the vacuum hose to make pressure on the exhaust side.
i heard later that he would drag out one of the blocks he had to mount the heads on to do his testing from inside the cylinders with an adapter to seal against the cylinder walls
I was really lucky to be able to meet and get to talk to him for a short while, I was installing his phone service after he moved from the coast out to the desert