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Porting ls1 heads- bowl of intake side?/short turn radius?
Hello forum,
I recently started porting my 241 5.7 heads and I want to know, is there anything else I should do to the bowl of the intake?( besides smoothing it out and taking off the casting) here are some pictures.
Also I’ve heard many things about the short turn radius. I’ve heard that I should take it down because that’s where most of the gains are. I’ve also heard not to reshape the short turn radius because shape is more important than how much you grind off the floor.
I guess my questions are:
Do I need to do anything else to the bowl of the intake?
Should I port the radius? If so how much do I port before hitting a water jacket? And what does the shape of the short turn look like after ported?
funny I just updated my old thread of the set of heads i home ported a long time ago. The images were screwed when photobucket decided to wipe them selves off the face of the earth but i just re-added them https://ls1tech.com/forums/generatio...l#post13251368
Well, I'm in the same boat, I was just lapping my valves, and looked at the bowl area. Decided to clean them up some, since it will be awhile before it's back together. So, I'm in any information I can get.
Check my link above. You dont want to do too much to the short side radius. I did a little bit to it to clean it up and straighten the radius out a bit but it should still be a nice consistent radius. From your pictures above you should take out the rocker boss on the roof of the runner.
I'd angle a little material off at the valve guide getting fairly close to the guide hole. Saw a pic of a professional done head in the diy link just posted to you where you can see this spot angled over.(post 20) I'd do just a little clean up enlargement after the valve seat.
a good professional 3 to 5 angle valve job is worth probably anywhere from 5 to 15 hp, so see if you can have that done some where.
In the actual combustion chamber removing material will lower your compression, but I'd very lightly clean up the highest surface of it & definitely flatten out any little high spots, as high spots are a detonation source.
Check out the pics in my Katech CNC thread. I don’t carbide cutter “port” the bowl. I use sandpaper cartridge rolls to carefully smooth/blend the bowl casting up to the seats I’ve even provided flow numbers for you to see what the factory GM valve job is capable of flowing
Don’t mess with the short turn. What you should do is work the steel seat where it intersects the alum there. Use your finger to feel that the whole area is smooth and a constant radius.
You never want to remove material from the floor.
The 243 Head has a much longer and more gradual intake short turn radius. That’s where the flow comes from.
A few years ago I found an excellent article from GM engineering on the 243 development. Sadly I didn’t book mark it.
If I’m not mistaken, Mamo patterned the AFR 205 after the LS6 Head.
Ports in the 205 are things of beauty.
and yes, no swirl ramp. No swirl ramps in the CNC stickers either.....
BTW, I had a junk 706 Head lying around so I removed the swirl ramp, then drilled a hole through the area and there is at least 1/8” of material left. So not that thin there.
And why mess with the 241 when the 706 is now the ****? 😊I’m porting up a set of 706 just because I’m bored. Maybe even get them flowed.Ron
Nah. The 243 is simply better. One magazine test doesn’t prove much.
It proves it sells magazines.
If you offered me a set of 243s, I'd junk the 706s so quickly and find a way to make the 243s work.
OP, as mentioned stay away from the SSR - not much to be gained there. Look at the way light cascades down the runner and around the obstacles. Light, like air, doesn't turn 90°. I just finished a quick (20hrs) port job on some 706s for our junkyard 5.3... don't forget there is an exhaust port too.
Nah. The 243 is simply better. One magazine test doesn’t prove much.
Truth....just wish there was a "all else equal" type say 10.5:1 (346") build/dyno that with a FAST 92 and the 228/232 sized cam that seems to be the perfect street set-up to let each head show it's worth/limitations if you will
I mean they do sell magazines but in the General's defense; each head has specific design parameters to fit the particular bore/stroke/piston/cam/vehicle application
Still crazy to me how the 243 with just about anyone's CNC program and the factory 2.00" diameter intake valve has put more street worthy cars in the ten second zone.........
those lingefelter heads are pretty nice. They are a little different because they are rectangle ports instead of cathedral ports like the 241/243's. One thing that would concern me are the CNC patterns in the chamber, that leave a lot of sharp points which could lead to hot spots/detonation. Weird they would leave it like that.
I ran my hand over these 241 heads many times, They were done on a machine program, ONLY removing what is necessary. Smoothing out every where to make them look nice can be to much, causing improper air flow.
I ran my hand over these 241 heads many times, They were done on a machine program, ONLY removing what is necessary. Smoothing out every where to make them look nice can be to much, causing improper air flow.
The ports are beautiful as expected. Im talking about the CNC markings left in the combustion chamber. there are sharp ridges from the bit the machine uses, highlighted in this picture. Im just surprised they did this in the chamber since sharp edges can cause hot spots/detonation.
12-28-2017, 03:09 PM
Porting ls1 heads- bowl of intake side?/short turn radius? 
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