porting tips for LS1 heads

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May 31, 2003 | 12:19 AM

#21

BIG PD

TECH Apprentice

Joined: Feb 2002

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From: tega cay, SC

Re: porting tips for LS1 heads

hey terry i lost 3rd and 4th gear the other day on my 7 month old 3 thousand dollar racing transimission so the money i was saving up for the heads may be gone now...i found something that it might be, but i don't think it is (hopefully though) but its lookin real grim on the whole heads option now. i'm bummed. ttyl

Sep 12, 2003 | 08:32 PM

#22

Raben

Launching!

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Re: porting tips for LS1 heads

What if you have access to a flow bench. Any tips for the home porters in that regard?

As I'm about to purchase a set of 99 LS1 Heads for under $200 Salavged to test with. Want to get the flow numbers as it stands and then play alittle and test again.

Any pointers to look for? I found some information on the net for LS1 porting http://www.sa-motorsports.com/diyport.htm

How accurate it is. .I have no idea. But willing to test myself if it means saving a thousand dollars or so

Nov 24, 2003 | 07:19 PM

#23

Trans Am Kid

Staging Lane

Joined: Nov 2003

Posts: 78

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From: Bedford, TX

I have been porting heads for a few years now and I thought I would try a set of LS1 heads for my car since I had a spare set laying around. A local shop has a flow bench they let me use for before and after test, here are the before and after numbers.

Stock
int. exh.
.50 34.0 23.5
.100 67.6 52.0
.150 91.3 77.0
.200 121.9 97.5
.250 150.8 114.3
.300 175.6 132.8
.350 198.0 146.5
.400 214.7 156.1
.450 222.2 163.8
.500 219.5 170.1
.550 224.7 175.7
.600 226.9 179.0

Ported with stock valves and 3angle valve jov
int. ehx.
.50 35.1 25.3
.100 65.5 55.7
.150 93.5 83.3
.200 142.1 105.4
.250 172.3 125.4
.300 207.1 143.9
.350 227.0 158.9
.400 249.3 179.9
.450 254.8 198.1
.500 266.7 209.2
.550 274.9 213.1
.600 279.7 219.0

Nov 25, 2003 | 01:00 AM

#24

ssheets

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From: Gardnerville, NV.

Quote:

Originally Posted by TVWilkes

We are offering very good prices on CNC ported heads.Just to clarify some things,there is no entering your measuremnts in a tape,going on in any modern CNC shops.The process to cnc port a head is very complex.There has to be a model (hand ported) to digitize,create your CAM drawing.Then you have to create toolpaths for the head.After the head is machined,valve job finished,HAND blended,you need to flow the head to see if it compares to the original ports.If not,you start all over.There is a lot of testing done before there is a finished product.After there is a product,testing goes on to make the heads better and better to keep up with the competition.I hope this gives a better understanding of the process.

You've got my vote.

Terry, as you know I've been shopping for a head cam package for a few weeks. I'm not sure about the cam yet, but the heads will be the PP 5.3l stage II shooting for 10.8-11.0:1 CR.

With what's at stake, I can not argue the value of your offerings.

(I'm thinking this post is worth a discount eh?

)

Seriously. most of us fall into to two categories. Those of us trying to make economical horsepower for our street abd occiasional racer or those of us seriously racing and trying to squeeze every last pony out of our motors.

Those in the former category can't go wrong with the PP off the shelf offerings. The extra cash you save can be used for other go fast mods.

Those that are seriously racing will have the justification to have their heads customized by some trick flow artist and will gladly pay the price.

I'm looking for an awesome street machine. If I can get ~425rwhp out of an 02 LS1 for less than $2,500 in parts and tuning, I figure I've got very little to whine about except maybe how fast my tires wear out

Last edited by ssheets; Nov 25, 2003 at 10:27 AM.

Nov 25, 2003 | 04:15 AM

#25

Scott Turvey

Launching!

Joined: Mar 2003

Posts: 250

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From: Oceanside CA

One issue with getting porting advice from the masses is making sure you're talking about the same castings. There are currently about eight different castings in the LSx family, and the port for one casting will blow a hole through another. I know, I've paid to have all of them done. Believe me, the initial cost of having a casting ported, tested, ported, holed, welded, ported, mapped, then translated to a CNC machine isn't cheap. As time passes and these port-profile costs become amortized, it'll get cheaper.