Head porting
Thread Starter
Teching In
Joined: Oct 2002
Posts: 4
Likes: 0
From: Washington
Head porting How thick is the short side radius on the LS1 head? I just want to massage it down a little, but don't want to ruin the head. An even bigger help would be if someone has a SHOT LS1 head I can cut in half.
Re: Head porting Welcome to LS1Tech Shadowhawk. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
You will have enough material to grind the short side radius without fear of water jackets. Use some common judgment though and don't grind excessively. Remember, shape is more important than size. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
As for finding a junk core, my suggestion is to make friends with the local GM dealers in your area and see if they can help you. A second option is to contact valvegod@aol.com and see if he can help you.
Good luck,
Richard <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
You will have enough material to grind the short side radius without fear of water jackets. Use some common judgment though and don't grind excessively. Remember, shape is more important than size. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
As for finding a junk core, my suggestion is to make friends with the local GM dealers in your area and see if they can help you. A second option is to contact valvegod@aol.com and see if he can help you.
Good luck,
Richard <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: Head porting Can you tell us what size your fully ported LS6 ports measure?Did you also measure swirl before and after? Just curious because those ports come larger and dont appear to need hogging unless the engine size is much larger than 346.Is your N/A 1/4 mile with these heads on 346?
TECH Addict
Joined: Dec 2001
Posts: 2,298
Likes: 2
From: new england
Re: Head porting Watch how much you grind short side because you wont hit water but you may ruin flow of head!
The work on the short side is the most critcal aspect of sucess versus failure on these heads. If you want pictures of anything it should be shortside radius of good flowing head not cutaway, IMHO. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
The work on the short side is the most critcal aspect of sucess versus failure on these heads. If you want pictures of anything it should be shortside radius of good flowing head not cutaway, IMHO. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
On The Tree
Joined: Jan 2002
Posts: 120
Likes: 0
From: Aloha, Oregon
Re: Head porting Having personally spent some 100 hrs porting my own set of LS6 heads and a lot of money having them flowed again and again, i can tell you that you will find your BIGGEST flow gains in the 1/2" before the valve and seat. Do not spend a lot of time cutting the short turns. I got 300+ cfm at .600 lift intake and 246cfm on the exhaust with this basic rule in mind. to answer your question, though, the casting at the short turn is ~.350", depending on core shift, of course.
FormerVendor
Joined: Apr 2002
Posts: 278
Likes: 0
From: Yorba Linda, CA
Re: Head porting Shape is critical at the short turn radius! This should be the last part of your porting job because the shape will depend on other final dimensions. Start in the "window area" (where the short turn radius starts - or where the port goes from square to round). Widen the window area and raise the roof (don't touch the short turn yet). Once the window is enlarged, blend it into the throat (just behind the intake valve). The throat diameter should be 85-90% of the valve seat size. Gasket match the port opening, and blend the runner back into the window area. Measure the new throat diameter. The short turn radius should be 1/4 of that arch. It's best to make a template to get the proper shape. As an example, if the window is 2.00"....scribe a 2.00" circle on a thin piece of steel or aluminum. Divide this into quarters, and cut out the area in the circle. This is the shape you need to form.
I hope this helps <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
I hope this helps <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
