SSmokinmaro

I dont know how many of you read "CAR CRAFT", but they just did a few large articles concerning the LS1 engines.

On a sidenote, i found VERY INTERESTING.. it said that LS1 heads with a TRIANGLE loooking mark near the spark plugs were cast better than heads withouth that mark (60% of heads carry this mark)...

the heads with this mark generally put down atleast 4-7 more RWHP than non-triangle marked heads..

just thought I would share..

-A

P.S. I checked, and my engine has the marks.. I checked some heads on ebay, some had it and some didnt....!!

Here is the EXACT wording of what the article says..

"Here's a secret: If you want the best heads for performance, make sure your heads have these small triangle marks below every spark plug hole. The marks are left by "chills" used during the casting process in GM's semi-permanent mold (SPM) tooling. Of these casting facilities that make Gen III cylinder heads, two use SPM tooling, the other heads are sand-cast. The SPM tools produce heads with very smooth, consistent ports and chambers which consistently dyno at least 4 to 7 hp better than the sand-cast heads."

December 2004, p.35

Lvmyz28

iTrader: (1)

Awsome factoid!

pdd

iTrader: (3)

ya, i read that also

HAMRHEAD

iTrader: (8)

Never knew that, interesting.

technical

Doesn't mean much once both types of heads are ported.

MrDude_1

iTrader: (4)

whats really funny:


the fastest stock internal guys that i know all have sandcast heads.

jrp

iTrader: (16)

i thought it was already known that die cast (241) heads had a higher cfm then the 98 - 00 sand cast :shrug:

SSmokinmaro

the 241, yes, does represent that it is the 2001 and newer LS1 head..

but..

the casting mark left on these heads are what set them apart from the others... not all heads have these, about 2/3 do though..

-A

technical

I believe JRP is trying to tell you that the casting mark signifies the newer style casting. #241 = Triangle = SPM = more CFM = 4-7 more HP.

jrp

iTrader: (16)

i believe the 317's are die cast as well, or its the 052's, i get them mixed up.

MrDude_1

iTrader: (4)

its not a newer STYLE casting.. same casting made with a diffrent technique.... the surface texture compare to the sandcast is smoother.

thats it.



the diff of airpressure in your tires matters more then that.. lol... like i said, there are ALOT of fast cars out there with the sandcast heads.... the diff is so slight that i wouldnt have it may any sway in choosing heads.

technical

Sorry, newer style casting process. :hair split:

MrDude_1

iTrader: (4)

not splitting hairs... just pointing out that they're the same shape...

so if you say..... go over the heads either by hand or have them ported, they'll have equal results.

saying they're a diffrent style would imply that the sand cast ones would be inferior design... when thats not the case.

technical

Read above....

https://ls1tech.com/forums/showpost....70&postcount=5

Much like a NASCAR RACE...we're going in circles.

02BlackBullet

iTrader: (60)

No triangles here...

Oh well, it's only a few HP.

Flareside

The heads are cast at two different places using two different processes. FYI, the GMPP LS6 CNC heads I have (243 castings) are mixed, one has the marks, one doesn't. Interestingly, GM (or LPE) ground down the triangle marks on the one that had them, probably to prevent cracking.

FELBER632

Of the hundred sets or so we've had go through the shop over the last few months since we've been keeping more of an eye on this factoid, I have found little rhyme or reason to it, other than they are manufactured at different foundries. There have been no particular casting numbers (The later ones anyway) that are one way or the other, whether it be 862/706s, 241/853, 317s or 243s. The "triangle" is definitely the nicer casting, and the main improvement IMHO is the chamber finish. As has been stated...If the head is ported/finished it won't matter. Also consider that I've seen identical castings that vary well over 4 HP from the factory that are identical sand,or die cast. So the 4HP number is pretty low when claiming something to be fact under a controlled test. JMO

Felber

technical

For some reason Patriot decided to ground the casting numbers clean off the pair of heads I bought from them. Can't figure out what they were trying to hide.

Ed Curtis

Mine just say "AFR"...



Ed

jrp

iTrader: (16)

same with the set i had tested, cast numbers on both heads were ground off, even inside the head by the rocker stands.


Ed, if i had 2200 bucks mine would say AFR to