2.055 Speedmaster Porting Progression

[Earlie A]

Working on some heads for the @NC Engine Builder cylinder head dyno testing. Engine break in and first testing is with bone stock Speedmaster heads. We also have several other out of the box heads to test, but it would also be nice to test a few modified heads. There are several modifications I would like to test and trying to determine the proper combination of changes is a little more difficult than first expected. The port in the test below was SUPPOSED to be a practice run on a Speedmaster head with a few basic modifications. I was hoping to put in a 2.055 valve job, enlarge the pushrod pinch, remove the head bolt bulge and blend the throat and chamber. The intent was to make changes that home porters could make (with the exception of the valve job) and then flow test to see the results. The valve job I used will require too much chamber and short turn work to be a 'basic' modification, so I'll have to try the basic route again. In the mean time I ended up trying some other things with this port. I was looking over the progress this morning and thought it might be interesting to a few of you to see an example of port progression.

The first test (1462) is a totally stock port with a single angle Speedmaster valve. The second test (1467) includes tubing the pushrod and head bolt holes, enlarging the pushrod pinch to the tube and to the gasket line, removing the head bolt bulge, cutting a 2.055 valve job 35/39/45/60/70/80, blending the throat and deshrouding the chamber within about 0.030" of a Felpro 1008 gasket. Throat size, bowl size and port volumes are listed on the spreadsheets. After test 1467 several changes were made which were basically addressing port volume or the short turn. A brief description of the changes for each test is shown in the 'Test Name' column. As of the last test, the throat was 90.3%, bowl width was 94.4% and port volume was 202cc.

As can be seen, on this style of head lots of time can be spent trying to improve the port above 0.500" lift. That's the area where the short turn becomes problematic and flow separation takes control of the port.

 

[Dart Frog]

Good stuff thank you!

 

[PRH]

We’ll see how the dyno tests unfold, but so far(from a flow vs effort standpoint) I’m liking the ootb TF’s(zero effort).

Just in terms of porting time, how long to take the intake port from zero to step 14, if you knew that’s where you wanted to end up?

Probably about 20 years ago now I did a basic full port job on a set of RPM heads. No tubes/no holes, 2.055 int valve, flowed about 280.
On an 11.5:1 419 with a port matched Victor/4500 carb and a very smooth easy on parts roller they made 587hp.

I always felt like with a ported intake and going up a step or two with the cam aggressiveness it might have broke the 600hp mark.

 

[Earlie A]

We’ll see how the dyno tests unfold, but so far(from a flow vs effort standpoint) I’m liking the ootb TF’s(zero effort).

Just in terms of porting time, how long to take the intake port from zero to step 14, if you knew that’s where you wanted to end up?

Probably about 20 years ago now I did a basic full port job on a set of RPM heads. No tubes/no holes, 2.055 int valve, flowed about 280.
On an 11.5:1 419 with a port matched Victor/4500 carb and a very smooth easy on parts roller they made 587hp.

I always felt like with a ported intake and going up a step or two with the cam aggressiveness it might have broke the 600hp mark.

I cannot disagree with the flow vs effort opinion on the TFs. They are impressive right OOTB. Such a tiny pushrod pinch though.

As far as time estimates, I can only say I have a an hour or two each day over the course of 6 days in steps 1-14. But that includes a lot of flow test and measurement time.

As far as our test goes, I'll be tickled to get over the 600hp mark. I would think an efficient 280-290 cfm with a fat mid lift curve would be sufficient.

 

[PRH]

I’ve made over 600hp from heads that flowed 280(not with a SBM though), so it’s def possible.

I’ll def be paying attention to the test results!!

Are you planning on having a set of heads to test that are done to that #14 level?

 

[ValiantRacing]

That is a really nice break down of what you did and the results, thanks for the information. and i think you don't need as much flow as people think to make good horsepower, it's all in the combo.

I currently run a set of SM with a 2.055 valve on my 340 in my race car.

 

[TurboGLH]

I'm really interested in the Bloomer heads vs the ported (CNC and Hand) SM heads.

 

[Earlie A]

There are so many things I would love to try. 45 vs 50 deg seats. 11/32 vs 8mm valves. Nail head vs tulip exhaust. But for me the big one is pushrod pinch area. If we run a test to isolate one parameter I would like that to be pinch area. But when pinch area is increased, other things downstream need to change as well. So what makes for a valid test? With time and monetary constraints, where is the best place to focus?

 

[MOPAROFFICIAL]

"Within .030 of a the felpro head gasket..."

Cylinder Bore - 4.030
Felpro gasket 4.180

Introduce the bores ledge into the chamber and see what it does.

 

[MOPAROFFICIAL]

There are so many things I would love to try. 45 vs 50 deg seats. 11/32 vs 8mm valves. Nail head vs tulip exhaust. But for me the big one is pushrod pinch area. If we run a test to isolate one parameter I would like that to be pinch area. But when pinch area is increased, other things downstream need to change as well. So what makes for a valid test? With time and monetary constraints, where is the best place to focus?

The valve job and a chamber on the straight side and across the far side.
I don't go bigger than the bore myself, but to each his own.

 

[Earlie A]

Are you planning on having a set of heads to test that are done to that #14 level?

My preference on a max effort set of heads is the TF. I have one set that will be tested OOTB. Maybe the max effort set comes later???

 

[Earlie A]

"Within .030 of a the felpro head gasket..."

Cylinder Bore - 4.030
Felpro gasket 4.180

Introduce the bores ledge into the chamber and see what it does.

I get, and I totally agreed with that position until I tried it. Little to no negative effect in my bench testing, but i have no idea what the effect on wet flow would be. The bevel on the top of the bore helps a little as well. I’m not arguing a point at all, just throwing out some thoughts.

 

[PRH]

My preference on a max effort set of heads is the TF.

I’m all for it(both ootb and rewrorked)……… your the “test master” of that endeavor.

 

[Dart Frog]

What does the cylinder bore need to be for a 2.055 valve on the speedmaster head to avoid any clearance or shrouding problems ?

 

[Garrett Ellison]

What does the cylinder bore need to be for a 2.055 valve on the speedmaster head to avoid any clearance or shrouding problems ?

According to our Late Great PBR, a typical 4.03 bore didn't require any notching with a 2.055, but a head gasket bore smaller than 4.18 would show more negative impact on valve and port flow through shrouding than whatever test bore size he was using on his bench.

 

[Earlie A]

What does the cylinder bore need to be for a 2.055 valve on the speedmaster head to avoid any clearance or shrouding problems ?

I would not foresee any clearance issues with any 340 or 360 based motor. As far as shrouding, if the chamber can be taken to at least the bore line there are gains to be made. As Garrett said above, PBR liked to deshroud out to the fire ring on the gasket.

 

[Dart Frog]

I run a 340 with a 4.070 bore and a 4.080 head gasket is that combination acceptable? Or would I benefit going to a larger head gasket?

 

[Earlie A]

I run a 340 with a 4.070 bore and a 4.080 head gasket is that combination acceptable? Or would I benefit going to a larger head gasket?

Maybe one of the engine builders on here will jump in and answer. Personally I don’t see any upside to a larger gasket if your chamber is good with the smaller one.

 

[cookietruck]

Dang. For a mild cam street motor, the SM heads with a 2.055 valve and nice valve job would really work well.

 

[MOPAROFFICIAL]

I get, and I totally agreed with that position until I tried it. Little to no negative effect in my bench testing, but i have no idea what the effect on wet flow would be. The bevel on the top of the bore helps a little as well. I’m not arguing a point at all, just throwing out some thoughts.

Knock the fuel out of suspension and wash that side of the bore perhaps, good question.

 

[MOPAROFFICIAL]

I run a 340 with a 4.070 bore and a 4.080 head gasket is that combination acceptable? Or would I benefit going to a larger head gasket?

Mls style?

 

[ValiantRacing]

I run a 340 with a 4.070 bore and a 4.080 head gasket is that combination acceptable? Or would I benefit going to a larger head gasket?

I have a 4.08 bore and a 4.08 gasket with a 2.055 valve, works great for me.

 

[273]

That is a really nice break down of what you did and the results, thanks for the information. and i think you don't need as much flow as people think to make good horsepower, it's all in the combo.

I currently run a set of SM with a 2.055 valve on my 340 in my race car.

Most mainly do cause it's easier to build a middle ground efficient larger engine then a highly efficient smaller one.

 

[Mean416]

Great post and thank you for sharing!

The more I see of this stuff the more I realize I wouldn't mess with my own heads.

 

[273]

Great post and thank you for sharing!

The more I see of this stuff the more I realize I wouldn't mess with my own heads.

Does the opposite for me makes me want to build a flow bench.