Hats off to Steve...061 flow results
 

Two years ago I set these heads up on a cnc mill. I raised the roof at the intake flange, removed most of the pushrod bulge and machined the bowl. After the bowl work, I said a few choice words and wondered why I machined them like that.

I bagged the heads up and six months ago decided to get them out and see if I could salvage them. I would like to thank Jim L., Calvin H., and Jim H. for their help. A special thank you belongs to Steve M. for the hours spent on the phone answering my endless questions.

Steve was extremely helpful and figured out how to fix my previous machining of the bowl. He also explained the reasons for the port shape, which is very interesting and helpful to know while grinding a port.

After the port work I took the head to the local machine shop and the flow on the intake at .500 lift was 294 cfm. The numbers were too good to believe. I then sent the head to Steve so he could flow it on his bench.

The intake port had a homemade radius plate with a 1.09 X 2.17 opening. The center exhaust port had nothing on the flange. Feet per second for the intake port is at the bottom of the flow sheet.

For anyone interested in photos or intake port sizes. Here you go. Stock, these intake and exhaust ports are taller than most other heads.

The intake entrance roof was raised .06 to 2.17. The width at the bulge is 1.09 and the stock entrance width was left alone. The raised roof was blended to the stock roof height above the apex of the short turn, which is 1.59. The width of the port at the apex is 1.54.

A two angle valve job with a 30 degree seat and a 60 degree undercut is used. The bottom of the 60 degree cut is 1.82 inches in diameter. The bottom of the bowl is 1.64 wide.

The short turn radius was reshaped to a .86 radius and moved back toward the intake flange as explained in Jim H's book. Thank you Jim for further explaining that to me.

The intake port volume measures 176 cc's.

First photo is the ported exhaust along with the milled only intake port. The exhaust ports in the other two photos are stock. Note the chamber shape of this 1967 061 head. I did mill the chamber floor because some of the valves were sunk, but the original chamber shape is retained.

Very interesting and nice #s. Thanks for sharing!

wow!! nice numbers!

So, what's their intended application???

Looks like Jim Hand did them, himself!!! ... :)

That is a great question, The 68 Firebird pictured below that my wife wants to race the boys on the street with. Maybe they will make their way to the GTO. A street/strip car that should be able to dial in at 12.00 for Sportsman racing.

I have not seen any Jim H heads, but I am sure they look good. I have seen some Steve M. heads and they are a work of art! Mine are far from that.

Theres excellent pic's of Jim Hands cyl. head work, in his book...the reason I know...

Wow I have a set of those laying around and thought they were worthless

As if the Intake divider & gasket corners were hardly modified.

That intake runner flow is at excellence. As if Oink 1 (Greg Merrick) did the work.
Do you know if 061 and Ram Air II have the same combustion Chamber? ( I see similarity, but observe RA II to have a recessed [dry] plug)
My R 96 A IIs are slated to receive such Intake porting this winter. On the fence with DIY or pay Oink 1.

If you donate blood, they check your iron content in your blood. If you are low on iron, you won't be, after all that grinding, on your heads...LOL

Did I read that correctly, that the port has 460-470fps for airspeed? Where in the port was that measured?
Wonder what a 45 degree seat would do for you.
Awesome numbers, you did a great job.

I missed something, I see a sheet showing Intake flow: @.500 273 cfm @.550 279 cfm. Where is the flow sheet showing 294 cfm? confused....

Let me clear up some things if I may in regards to Toms post on his 061 heads.

1) When he finshed the porting work he took the heads to a local shop near him in Iowa to get flow tested.
I told him to make sure that they calibrate or have calibrated the flow bench on the day that they do the flow test.
Tom called me back and said that they have a orfice plate to calibrate the bench but they do not know how to use it, so the flow test was done with a peak intake flow number coming in at 294 CFM.
Knowing that the dimentions I told Tom make/grind the intake valve bowl throat at(1.77") I new that their was no way the port could flow 294 CFM, which turned out to be some 8% too high when I bolted his head to my bench here in N.Y and then did the flow test, which peaked at 279 CFM as seen on first the flow sheet of mine that he posted.

2) Toms second posting states that these 061 heads have taller ports than the other D-port heads, what he ment to say was they have taller short turn heights it seems than the other heads due to the shallow one of a kind combustion chamber shape that these heads have.
A foot note would be that from what I recall the # 48 heads have the same exhaust port short turn shape, but may be not the height?

3) the RAII head has the same basic combustion chamber shape on the spark plug side of the chamber as these 061 heads, but the shallow/quench side of the 48 is just like all the other D-port heads.

4) the feet per second number where taken on the intake port floor right in the center (left to right) of the short turn and right about at its apex.
This is alot of air speed, but the port is moving a bunch of air for its cross sectional area which is the key to moving#( 1) a heavy car and #2 having a motor that is very rev happy from idle up to its rpm of peak torque with out crazy stiff gearing!
Another way to look at it is that at the intakes ported size of 176 CCs, which is only some 13.5% larger than stock, the head is flowing 74 CFM more than stock, which works out to being 36% more flow over stock. So yes, all that air passing thru that size port makes for alot of FPS!

5) Applying a 45 degree seat with the current port shape would pick up the high lift flow numbers by about 4 to 5 CFM, while dropping the lower lift flow numbers by 6 to 10 CFM unless you add a 30 degree back cut to the intake valve.
At that point the low lift numbers would only lag some 3 to 5 CFM behind the 30 degree seat numbers.
If you spent another 2 hours of grinding time on the port and took the throat size out to 1.84"(a bit of a risk of grinding thru) re-ground the short turn to the needed raidus, and then raised the roof more thru the window and out to the flange you would then have stable air flow numbers in the 292 CFM range with a 30 degree seat added by the 061s short turn height!

Both of my flow test where conducted on a 4 1/8th" bore and temperature/pressure corrected to 28" H2O.

The only question I have about these 061 heads is what will be their nature towards pinging or not due to their wide chamber shape?

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Note 3) Ah, so that's why they look similar to RA IIs.
Note 4) No issue with fps value, but would like to know the LOWEST fps value too. Really the fps uniformity across the runner about 2" in.
Note 5) RA II is ping-resistant compared to the 48's RA III combustion chamber: I run 87 Octane Street, 89 Octane Strip yet 455+060 with 38cc dish for ~9.0:1. I credit the DRY sparkplug.

Grab a die grinder and get to it. Have fun with them. I think they would flow pretty good doing half the work I did. I read someone called them a poor mans ram air head. The ports are taller and the bowl is a little larger than my 1971 # 96's.


I did not see a reason to post that flow sheet. Just wanted to tell the story. Their was a higher flow # at an higher lift. I just told about the 294 cfm at .500 lift because it seemed the most impressive, or should I say inaccurate.


That is correct on the FPS. Air moving 1 1/2 football fields in one second, unreal. I thought about a 45 degree seat as I know you like and use that. I wanted to stay with what Steve was teaching me.




If I use an RPM intake, I plan to leave the head opening width untouched. The RPM's width is cast narrow so I will try to have the intake exit 1.09 to match the width at the bulge.

Or do you guys think I should widen the intake manifold's ports to 1.13-1.16 and have it match the factory opening of the heads?

I wanted this to be a factual porting thread, not sure if I like the porting work being compared to the oink man.

Here is a site to compare the 061 and ra2

http://futom.tripod.com/id96.htm

That's a true statement/concern it wouldn't be a fair comparison between the two. On one hand you have Greg Merrick a life time Pontiac builder and arguably one of the best "Pontiac" head porters in the world. On the other hand you have "A" guy from Iowa that ported "A" set of heads. I agree there's no comparing the two. JD

Tom, as for my 2 cents on the manifold, I would leave it at its as cast width and just grind the roof to match your port.
I would then spend time on the short plenum getting the turning riadus much fatter into the runners and blend those up into a 1 " carb spacer if you have the hood height for such.
The tall plenum side with the spacer will flow the needed numbers as is with the spacer.

My Manifold thoughts are to grind the Manifold Dividers "paper-thin" an inch or more in, to improve the flow trajectory past the ported-pushrod-bulges. I plan to inspect that on me manifolds.

Did you flow the heads at a pressure above 28"?

Tom put them on the GTO and bring it to Cordova.

Enhancing my already-clear Post: Grind the Manifold divider, not the Head divider, for Flow trajectory improvement past the Pushrod bulge.

Grinding the common wall at the flange like that only helps out the inboard ports to provide more area, on the out board ports its the push rod buldge that piches things down.

In regards to testing above 28", no as my Super Flow bench (the 110 model like Jim Hands and Rock from HHP mag) can only do a max of 15"h20, we than have to do the math to convert up to 25 or 28".

I am not totally sure, but I think "Oinky" has hung up the grinders and wrenches. Health reasons. He will still talk your leg off if you call him. If you have a Pontiac question, he is always willing to help.

Say it isn't so.

Yea okay, Good Point. inner CYLs 3 4 5 6 benefit from grinding Manifold divider per me prior Post claim). I was thinking the outer CYLS 1 2 7 8, would benefit depending on the intake runner trajectories.

Mr Half. I have ported to the felpro 1233 gasket size in the past ( 1.18 wide ) but a few years later decided that staying with less width is better (this is the street forum ).

I know years ago the some stock class racers, where you could not port the heads, would build up the intake manifold port to match the width at the bulge in the head. Making the smaller width a more gradual flow path instead of the bump at the bulge.

Many years ago I spoke with Pete McCarthy and he told me not to port the bulge at all. The idea is to have only one venturi in the flow path and he said have it at the bulge.

Jim Hand also told me the bulge is not much of a restriction, just reshape it. Again, thank you Jim for your help.

Let me detail more my reply on the FPS question some post back on this thread.

460 FPS would be concidered fast, too fast for a race only motor looking for a 1000 to 1500 rpm wide torque peak to hp peak power band.

That being said, for a street/strip motor ( a bit more street than strip and over 3300 lbs)that will not be called on to make more than 550 to 575 hp, then FPS number in the 460 to mid 470 range will work very well.

Again, that being said for a race only motor anything over 350 to 400 FPS dependant on port shape will cut into the torque and hp number that could be had in a 1k to 1.5k power band.

When I have a head for full race use on the flow bench and my peak flow numbers come in along with FPS numbers over the 350 FPS mark I will do what needs to be done shape and/or area wise to get the FPS numbers back in line, EVEN IF IT COST 3% OFF OF THE PEAK AIRFLOW NUMBERS, on the race track the car will be faster!!!

Many times in this situation its best to just slow down the air mass by knocking back the push rod buldge more if you have some left to knock back, but you need to let a velcocity probe guide you in this, by this I mean that dependant on your port width on the roof as you get to the window area, some times kicking back the push rod buldge more top to bottom will put you in a catch 22 situation by where making the this area wider has slowed down the air flow on floor and up to mid port height, but the increase in width from the mid point up to the roof just lets more air mass be admitted and hence the velocity difference between the floor at the crown/apex and roof is now even greater than before!
The result being your back at square one again.

Tom, in regards to Pete`s reply about the venturi area, a more proper term to use is port choke area.
To this regard in a full on race motor you want to have only one port choke in the whole Intake track, and this choke needs to be one stroke lenght up stream from the back of the Intake valve.
To this end and in regards to most stock Pontiac motor stroke lenghts, the choke ends up being in the location of the stock push rod buldge.
Another concideration to the max race motor is that this area from the back of the valve to the choke needs to contain the volume needed to fill the cylinder to atleast 100% VE.
Things start to get real crazy now math wise as you might invision!

Steve,

You amaze me. Thank you for sharing yet another useful tip on the seemingly secret head porting technique. Just how many more do you have?

Many years ago the Pontiac was put down as a car/engine that was not fast, you older guys remember this. We had the heads, just not the knowledge to make them flow better. I wish I had properly ported heads back in the old days of young guys street racing.

Thanks again, Steve

Alot of these so call secrets where very kindly pass on to me by others so I`am just sharing, and hopefully doing the same good!

In some magazines and forums this info is referded to as tricks so as to generate sales.
That really pisses me off as the word trick infer`s magic, and their is no magic in making a car perform better above a certin HP level, you eitheir know what your doing or you do not and have to refere to other folks level of info to step you up to the next performance floor!
I too got into porting back in my younger days to keep up with my buddys cars that both had less lbs to drag around had heads that flowed way better than the 389 heads I had on my boat of a 65 GP.
I remember all too clearly saying to myself that with the amount of time I put into porting (grinding with a electric drill and some stones, lol) some 670 heads that I picked up for the motor that surely I now had some killer flowing heads!!

I came to find out that once I got my flow bench and testing those same 670 heads that a measly 230 CFM, or plus 25 was all I got extra out of them on the intake side.
Now lets fast foward to your heads Tom and on your first guided try picked up 75 CFM!!
It`s good to have friends no?