Sportsman 11 Porting

General engine tech -- Drag Racing to Circle Track

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wilson1970
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Sportsman 11 Porting

Post by wilson1970 » Tue Jun 05, 2018 5:55 pm

Any good tips on where SBC Sportsman 11 heads need the most work as far as cleanup or hand porting?
Pics ars welcome . Thanks

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Re: Sportsman 11 Porting

Post by MELWAY » Tue Jun 05, 2018 6:00 pm

Chop the guide boss down and blend the bowl to start
Chamber also needs some work to make it breath

They are great heads when touched up
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Re: Sportsman 11 Porting

Post by Kbails » Tue Jun 05, 2018 8:35 pm

use the search function there are a few good threads on this casting. but i believe like melway said wack the huge guide down a bit, a good bowl blend and a quality valve job should get you 75% of the gains you would get from paying for a "full" porting job.. if that makes sence
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wilson1970
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Re: Sportsman 11 Porting

Post by wilson1970 » Tue Jun 05, 2018 8:36 pm

Yes it does. These guides are huge....

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Re: Sportsman 11 Porting

Post by Kbails » Tue Jun 05, 2018 9:07 pm

viewtopic.php?t=43087

some pics here /\
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Re: Sportsman 11 Porting

Post by BOOT » Tue Jun 05, 2018 9:39 pm

Might wanna open up the pushrod holes(towards the rocker studs a bit) while your working on the heads if you plan to use/try higher ratio rockers.

Don't dig out behind the intake guide as it exits.
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Re: Sportsman 11 Porting

Post by mag2555 » Thu Jun 07, 2018 7:46 am

Grind the common wall over as far as you can/ dare to get a straight run to rear wall of the bowl.
I forget what the valve to Throat percentage is in these Heads out of the box so I need to dig out some flow sheets to make any more recommendations that what I and others have done here.

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Re: Sportsman 11 Porting

Post by Frankshaft » Thu Jun 07, 2018 8:52 am

Is this for the 355 that you have asked this 3 times now? I gave you a good summary on what to do on one of the threads. Not sure what else you want to hear?

I just looked, haven't figured out how to post a link to a post on here, actually, the advice I gave you was actually really good, and would really wake up those heads.

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Re: Sportsman 11 Porting

Post by resurrectionjoe » Thu Jun 07, 2018 11:54 am

Frankshaft wrote:
Thu Jun 07, 2018 8:52 am
Is this for the 355 that you have asked this 3 times now? I gave you a good summary on what to do on one of the threads. Not sure what else you want to hear?

I just looked, haven't figured out how to post a link to a post on here, actually, the advice I gave you was actually really good, and would really wake up those heads.
Here it is your reply from 6 months ago Frankshaft.

Seems like good info to me.


Post by Frankshaft » Mon Jan 01, 2018 1:57 pm
For a 355, I would stick to the basics. streamline guide bosses, they are huge, roll short turn, and I would install 2.055 intakes for no other reason to improve the stock valve job. Its pretty crappy. It reminds me of how gm did it back in the day. Big 70 throat cut, minimal bottom angle, and terrible top cut to chamber transition. Doing something like a 38-45-60-75 intake, with a nice top cut to chamber transition, keep throat at small size for 2.055 valve, 88-89%. Exhaust, a 39-45-with a radius under the seat into the bowl. About 86% throat. To get that intake seat, you will need to install the bigger valve to gain back the material, because that aggressive 70 degree cut removed it. Or, a 40-50-65-75 intake seat with the 2.02, size throat about 91%. There should be material to get all the angles in with the 2.02 valve, 50 degree seat. Only issue, your current valves, may not have enough margin to change the angle from 45 to 50. The rest of the intake port doesn't need to be touched. It has a fairly generous cross section, and nice complementing areas, pushrod pinch is also about 2.3 untouched, leave it alone. All the gain for your application will be in the bowl, short turn, valve job and chamber. The exhaust port is plenty big as well. Same mods, guide boss, bowl, short turn, valve job and chamber. The good news, is less is more here.

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Re: Sportsman 11 Porting

Post by rewguy » Thu Jun 07, 2018 1:21 pm

"ask-hole" (definition) - someone who asks you a question, which you take time and thought to answer...........Only to ask twenty more people the same question later. Making it seem like a complete waste of time answering them in the first place. If you're going to trust someone enough to ask them in the first place, then take their advice implicitly. Don't insult them by continuing to ask others until you get the response you're after. Not saying this necessarily applies, but in this line of work....it gets old. Quickly.

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Re: Sportsman 11 Porting

Post by groberts101 » Thu Jun 07, 2018 1:51 pm

rewguy wrote:
Thu Jun 07, 2018 1:21 pm
"ask-hole" (definition) - someone who asks you a question, which you take time and thought to answer...........Only to ask twenty more people the same question later. Making it seem like a complete waste of time answering them in the first place. If you're going to trust someone enough to ask them in the first place, then take their advice implicitly. Don't insult them by continuing to ask others until you get the response you're after. Not saying this necessarily applies, but in this line of work....it gets old. Quickly.
I get your point here.. but that is also a sure fire way to get sucked into narrow minded viewpoints. No one person knows it all and cross referencing various viewpoints from several trusted and respected sources helps to refine you own and allows more pinpointed direction in where to apply certain rules or tricks.

On the other hand.. if you don't try what input was given at least once to correlate its effectiveness.. how do you know who's closer to being right on target and which direction to go from there? Trial and error is unavoidable no matter who tells you what. Especially with engines where even small and seemingly inconsequential changes cause differing results.

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Re: Sportsman 11 Porting

Post by Frankshaft » Thu Jun 07, 2018 2:00 pm

groberts101 wrote:
Thu Jun 07, 2018 1:51 pm
rewguy wrote:
Thu Jun 07, 2018 1:21 pm
"ask-hole" (definition) - someone who asks you a question, which you take time and thought to answer...........Only to ask twenty more people the same question later. Making it seem like a complete waste of time answering them in the first place. If you're going to trust someone enough to ask them in the first place, then take their advice implicitly. Don't insult them by continuing to ask others until you get the response you're after. Not saying this necessarily applies, but in this line of work....it gets old. Quickly.
I get your point here.. but that is also a sure fire way to get sucked into narrow minded viewpoints. No one person knows it all and cross referencing various viewpoints from several trusted and respected sources helps to refine you own and allows more pinpointed direction in where to apply certain rules or tricks.

On the other hand.. if you don't try what input was given at least once to correlate its effectiveness.. how do you know who's closer to being right on target and which direction to go from there? Trial and error is unavoidable no matter who tells you what. Especially with engines where even small and seemingly inconsequential changes cause differing results.
You just summerized the answer to all your questions on the 50 degree seat thread, lol.

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Re: Sportsman 11 Porting

Post by statsystems » Thu Jun 07, 2018 2:01 pm

groberts101 wrote:
Thu Jun 07, 2018 1:51 pm
rewguy wrote:
Thu Jun 07, 2018 1:21 pm
"ask-hole" (definition) - someone who asks you a question, which you take time and thought to answer...........Only to ask twenty more people the same question later. Making it seem like a complete waste of time answering them in the first place. If you're going to trust someone enough to ask them in the first place, then take their advice implicitly. Don't insult them by continuing to ask others until you get the response you're after. Not saying this necessarily applies, but in this line of work....it gets old. Quickly.
I get your point here.. but that is also a sure fire way to get sucked into narrow minded viewpoints. No one person knows it all and cross referencing various viewpoints from several trusted and respected sources helps to refine you own and allows more pinpointed direction in where to apply certain rules or tricks.

On the other hand.. if you don't try what input was given at least once to correlate its effectiveness.. how do you know who's closer to being right on target and which direction to go from there? Trial and error is unavoidable no matter who tells you what. Especially with engines where even small and seemingly inconsequential changes cause differing results.

And then you get exactly what you get right here. Analysis by paralysis. You get just enough contradicting views to keep you from doing anything.

There has been enough information for someone wanting to learn to get going and make his own decisions. Or he can let fear rule his world and do nothing or continue on doing what you are doing.

statsystems
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Re: Sportsman 11 Porting

Post by statsystems » Thu Jun 07, 2018 2:01 pm

Frankshaft wrote:
Thu Jun 07, 2018 2:00 pm
groberts101 wrote:
Thu Jun 07, 2018 1:51 pm
rewguy wrote:
Thu Jun 07, 2018 1:21 pm
"ask-hole" (definition) - someone who asks you a question, which you take time and thought to answer...........Only to ask twenty more people the same question later. Making it seem like a complete waste of time answering them in the first place. If you're going to trust someone enough to ask them in the first place, then take their advice implicitly. Don't insult them by continuing to ask others until you get the response you're after. Not saying this necessarily applies, but in this line of work....it gets old. Quickly.
I get your point here.. but that is also a sure fire way to get sucked into narrow minded viewpoints. No one person knows it all and cross referencing various viewpoints from several trusted and respected sources helps to refine you own and allows more pinpointed direction in where to apply certain rules or tricks.

On the other hand.. if you don't try what input was given at least once to correlate its effectiveness.. how do you know who's closer to being right on target and which direction to go from there? Trial and error is unavoidable no matter who tells you what. Especially with engines where even small and seemingly inconsequential changes cause differing results.
You just summerized the answer to all your questions on the 50 degree seat thread, lol.

Beat me to it. Make a decision about what you want to do and move on.

groberts101
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Re: Sportsman 11 Porting

Post by groberts101 » Thu Jun 07, 2018 5:20 pm

statsystems wrote:
Thu Jun 07, 2018 2:01 pm
Frankshaft wrote:
Thu Jun 07, 2018 2:00 pm
groberts101 wrote:
Thu Jun 07, 2018 1:51 pm


I get your point here.. but that is also a sure fire way to get sucked into narrow minded viewpoints. No one person knows it all and cross referencing various viewpoints from several trusted and respected sources helps to refine you own and allows more pinpointed direction in where to apply certain rules or tricks.

On the other hand.. if you don't try what input was given at least once to correlate its effectiveness.. how do you know who's closer to being right on target and which direction to go from there? Trial and error is unavoidable no matter who tells you what. Especially with engines where even small and seemingly inconsequential changes cause differing results.
You just summerized the answer to all your questions on the 50 degree seat thread, lol.

Beat me to it. Make a decision about what you want to do and move on.
Why? I'm asking experts to clarify vague generalities they've painted with wider than typically accepted brush strokes. Maybe some don't really know everything there is to know about a subject but are afraid to fall off such a high horse for fear of others finding out is was really only a pony?

And I've quite literally read through hundreds or your regurgitated opinions gleaned from others that then magically turned into your own firsthand experiences over the years here. False pride is a virtue for some who like to build facades to show superiority over others. Maybe some of this stuff still eludes me.. but I sure as hell know psychology and am rarely paralyzed by fear. My biggest fears revolve around lost money and time.. I couldn't care less about injured pride caused by failure. Only makes me smarter and stronger in the long run.

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