SM Head Modifications on a budget

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pittsburghracer said:
Do you remember a few weeks ago when it said in one of MY posts to remember three words. Push push push. Almost any head you look at will have what I refer to as a “Herman Munster” overhang at the short turn leading into the valve job. It’s hard to see in Brian’s pictures but on the left side you can see how he “pushed” Herman’s forehead back. This helps you shape the shortside and at the same time widens the shortside. Like others have said you may not have to widen the pinch, till you do. As you learn you will find you go back and forth finding the areas that need work. Those of use that have done this for years can aggressively attack each area from experience. Study this picture and think about how pushing this area back will benefit you. Remember as you lay down and “tighten up” your corners with smaller tools you are not only gaining area but access too.

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So are we closing the book on steps 1 through 5, the initial scope of this post? If so I would like to wrap it up a little before moving on.
 
Earlie A said:
So are we closing the book on steps 1 through 5, the initial scope of this post? If so I would like to wrap it up a little before moving on.
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You are probably way past what 80% of the guys would go. It was an interesting experiment that I thank you for taking the time to partake in. Probably the only thing that would interest me right now would be what would a nice gasket matched single plane intake do for this. Would it slow down the airspeed enough to let the numbers on your last flow test continue to climb instead of stall and drop. Would it calm it enough to keep pulling up to .580 lift. Thanks again for your effort
 
In my mind, with the bigger valve and pinch/bulge work, the port is begging for some attention in the SSR area.

Has the 5” port extension been tried on any of these later stages?
 
pittsburghracer said:
Do you remember a few weeks ago when it said in one of MY posts to remember three words. Push push push. Almost any head you look at will have what I refer to as a “Herman Munster” overhang at the short turn leading into the valve job. It’s hard to see in Brian’s pictures but on the left side you can see how he “pushed” Herman’s forehead back. This helps you shape the shortside and at the same time widens the shortside. Like others have said you may not have to widen the pinch, till you do. As you learn you will find you go back and forth finding the areas that need work. Those of use that have done this for years can aggressively attack each area from experience. Study this picture and think about how pushing this area back will benefit you. Remember as you lay down and “tighten up” your corners with smaller tools you are not only gaining area but access too.

View attachment 1716267434
Click to expand...
Been reading 8 pages of the interesting speed master head work, about the only I understand was the "Herman Munster's forehead" analogy :thumbsup:
 
Earlie A said:
Sort of the same thing happens when the PRP is opened without changing the SS. It exposes the other problems. The factory sizes the PRP the way they do for a reason.

I watched a Youtube video with Curtis Boggs and Jeff Hammond. Curtis talked a bit about monitoring pressure differentials (pressure drops) in different parts of the port to help really figure out what's going on with these low port heads. I think that would apply here.
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I watched about a third of that interview and forgot to watch the rest of it.

I need to go find it and finish watching it.

IIRC he said he was not a big port speed guy. Probably watch it from the beginning.
 
Shortly after these RPM copies came on the scene someone sent me one to see if there was any “low hanging fruit” for big gains in flow.

It was several years ago, but I remember my takeaway being, after the valve job and blow blend/SSR tweak are done……. which gets you into the 260’s……..that you have to do some meaningful actual “porting” to get much past that point.
 
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I don’t know if PBR keeps track of his time while porting, but since he’s quite familiar with porting these heads into the 290+ range, I’d love to know how long it takes him to do the complete porting(just the porting) for one intake port.
From as cast to the final touches of burr finish.

I would think by this point in the game, for that flow level there’s no more R&D……… you’d just go in and get it done.
 
PRH said:
Shortly after these RPM copies came on the scene someone sent me one to see if there was any “low hanging fruit” for big gains in flow.

It was several years ago, but I remember my takeaway being, after the valve job and blow blend/SSR tweak are done……. which gets you into the 260’s……..that you have do some meaningful actual “porting” to get much past that point.
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The exhaust side is so easy to make some fast unbelievable gains. Maybe not so much in flow but performance. 220 cfm on that side is probably a good job. One of these days I’m going to grab a head and just give in a nice performance valve job for a 2.02 valve, 30 degree backcut, 15 degree chamber cut, and spend a fair amount of time on the short side. Then do up the pinch and bolt bulge. I won’t touch the roof or floor except to blend the work I do on the short side.
 
pittsburghracer said:
The exhaust side is so easy to make some fast unbelievable gains. Maybe not so much in flow but performance. 220 cfm on that side is probably a good job. One of these days I’m going to grab a head and just give in a nice performance valve job for a 2.02 valve, 30 degree backcut, 15 degree chamber cut, and spend a fair amount of time on the short side. Then do up the pinch and bolt bulge. I won’t touch the roof or floor except to blend the work I do on the short side.
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Here’s how I remember my test looking for the easy stuff.
Valve job, back cut, blend bowl & SSR = low 260’s.
Open pinch - basically no gain
Smooth bolt bulge - basically no gain

I’d love to see how it worked out for you.

With what I did the SSR was still an issue, so making improvements upstream weren’t paying off without more of “something else” getting done.
 
PRH said:
I don’t know if PBR keeps track of his time while porting, but since he’s quite familiar with porting these heads into the 290+ range, I’d love to know how long it takes him to do the complete porting(just the porting) for one intake port.
From as cast to the final touches of burr finish.
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I do not keep track of time as I charge per job. I honestly probably wouldn’t want to know what I make per hour. Like I said earlier I set a head up in my rotator and do every pinch, then every bolt bulge, then every roof, every common wall, lots of work to the pushrod wall from pinch to bowl, then address the bowl and shortside. Usually then the chamber, valve job, set my short side height and shape, spark plug holes and shape brass. Exhaust is when I need a break.
 
I certainly appreciate all the willing participants and mentors. I feel like I have gained some understanding of the whole process through this exercise. I hope to spend a little time the next few days cleaning up some loose ends and trying a couple more things. I don’t expect much until addressing the SSR, but I’ve got to try. I also owe it to Yellow Duster to try a couple of exhaust tests. Thanks again guys.
 
Earlie A said:
I certainly appreciate all the willing participants and mentors. I feel like I have gained some understanding of the whole process through this exercise. I hope to spend a little time the next few days cleaning up some loose ends and trying a couple more things. I don’t expect much until addressing the SSR, but I’ve got to try. I also owe it to Yellow Duster to try a couple of exhaust tests. Thanks again guys.
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Thank you
 
PRH said:
In my mind, with the bigger valve and pinch/bulge work, the port is begging for some attention in the SSR area.

Has the 5” port extension been tried on any of these later stages?
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Great idea on the extension. I’ll try that soon.
 
pittsburghracer said:
You are probably way past what 80% of the guys would go. It was an interesting experiment that I thank you for taking the time to partake in. Probably the only thing that would interest me right now would be what would a nice gasket matched single plane intake do for this. Would it slow down the airspeed enough to let the numbers on your last flow test continue to climb instead of stall and drop. Would it calm it enough to keep pulling up to .580 lift. Thanks again for your effort
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Unfortunately the best intake I have is an RPM Air Gap and it is on a car. I have several factory iron ones. They should calm a port down quite well.
 
PRH said:
In my mind, with the bigger valve and pinch/bulge work, the port is begging for some attention in the SSR area.

Has the 5” port extension been tried on any of these later stages?
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Here's the short 3/4" thick entry plate vs the long 5 1/2" tapered entry plate. This really didn't hurt flow as much as I thought it would. It also calms the port down some like PBR mentioned. The curve looks much like a curve with a tight pushrod pinch. That PRP calms the port down as well.

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PRH said:
My next step would be a quick and easy one…….

Clay in the sharp corner in the chamber that was left by the edge of the 15* cutter……..so it’s like the cut was made with a blade that had a radius on the OD.
It probably won’t do anything at this point, but it would be nice to have the chamber form more “correct” moving forward.

My take on where it’s at right now is……… the SSR is still in control at the higher lifts.
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Here's a test with the inside corner filled in with clay at a radius of 0.2". This was somewhat beneficial at low lifts and again at high lifts. At 0.500" lift it appears to hurt flow, but that is somewhat misleading. At 0.500" lift the air flow is right at the point of separating from the short side. As a matter of fact, the manometer fluid is bouncing around quite a bit at this point as flow separates and reattaches. If anything, the sharp corners are helping flow stay attached a little longer so the cfm hits 265 vs the 260 for the clay radius port. I like the look of the radiused inside corner curve better. Average cfm over the range is better as well.

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So, after following this thread to its entirety, one take that I get it that someone really needs a flow bench to make sure that each port flows the same. Otherwise, you will have a cylinder that will be just "along for the ride".... Like a fat kid on a rowing team.
 
85glht said:
So, after following this thread to its entirety, one take that I get it that someone really needs a flow bench to make sure that each port flows the same. Otherwise, you will have a cylinder that will be just "along for the ride".... Like a fat kid on a rowing team.
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That's funny.

So far, I think we have seen a few things that definitely pay off, all of them right around the valve area. A good valve job, backcutting the valve and a light bowl blend all add up to 15 cfm so far. Modifying the PRP and head bolt bulge are not great short term moves but unlock potential for future modifications. I'm going to continue to play around with the valve job and simple chamber and bowl mods before moving on to the SSR. I really think there's 5-8 more cfm waiting to be found.
 
85glht said:
So, after following this thread to its entirety, one take that I get it that someone really needs a flow bench to make sure that each port flows the same. Otherwise, you will have a cylinder that will be just "along for the ride".... Like a fat kid on a rowing team.
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Even if you had the flow very consistent which you can do an intake runners with different turns, entry angles, and lengths change things up. Don’t ask me how but if a port is right it will balance out and run great. What I don’t like to see is what I see on the small block TrickFlow heads. I know I can get an Edelbrock head in the low 9’s. I’m not so sure about a TrickFlow head. Low 10’s, heck ya.
 
Earlie A said:
Unfortunately the best intake I have is an RPM Air Gap and it is on a car. I have several factory iron ones. They should calm a port down quite well.
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From the testing I’ve done with this style intake it’s a great street intake. Even some street strip, but if you want nice horsepower move up to a single plane
 
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