l92 vs 317's
#3
TECH Regular
iTrader: (9)
Join Date: Dec 2007
Location: Ohio
Posts: 460
Likes: 0
Received 0 Likes
on
0 Posts
You going to need a good porter and milling to up your compression. Even then the L92/LS3 heads are the way to go. They flow amazing out of the box and they are dirt cheap. Port and mill some L92 heads and make big power.
#6
TECH Enthusiast
iTrader: (7)
L92's flow 320 cfm @.600 lift, right out of the box uncut in rough cast. They have 260cc intake runners which are larger than most aftermarket LS heads. They also out flow a lot of aftermarket LS heads. With an intake runner that big they do suffer a bit on the air speed. They suffer from low velocity. Hell they don't even wake up until 3k rpm's. My L92'd 6.0 feels lazy down low because of the slow moving air in the runner. But is not that noticeable because the truck only weighs 3k lbs. This is where a 317 head can out perform an L92 down low, since they have a 210cc intake runner. So they have more velocity at low valve lifts and lower rpm's because of the smaller/narrower runner. But beware...when an L92 head comes alive...I hope you're going in a strait line 'cause the tires WILL break loose. I can smolder the tires at freeway speeds.
Last edited by tennerv8; 11-23-2011 at 12:07 PM.
#7
Launching!
iTrader: (1)
Broad strokes answers.
L92 heads are great, but they require more thought on cam choice due to the large port. - Very easy to overcam.
The smaller cathedral ports on ported 317/243 heads will be a bit more dummy proof regarding cam selection, and will be more tolerant of overcamming.
The moral of the story....pick the right cam and you can make great power. (regardless of head choice,)
L92 heads are great, but they require more thought on cam choice due to the large port. - Very easy to overcam.
The smaller cathedral ports on ported 317/243 heads will be a bit more dummy proof regarding cam selection, and will be more tolerant of overcamming.
The moral of the story....pick the right cam and you can make great power. (regardless of head choice,)
Trending Topics
#8
TECH Resident
Seems like you could make a fairly good case for L92's on a track car and 317's for street use. GM uses very small cams compared to what most of us are accustom to so the L92's work great on the street, for factory cars.
I have also read that on a 4" bore the L92's cause a flow restriction because of shrouding the jumbo valves...when you get into the 460+ rwhp range.
I have also read that on a 4" bore the L92's cause a flow restriction because of shrouding the jumbo valves...when you get into the 460+ rwhp range.
#10
TECH Resident
This article may help answer some questions. Several cam tests with L92 heads...
http://www.hotrod.com/techarticles/e...camshafts.html
http://www.hotrod.com/techarticles/e...camshafts.html
#11
Launching!
iTrader: (1)
Pushing 2900lbs to 9.87@137 with a stock junkyard longblock is pretty dang impressive in every way measurable.
If your goals are in line with Dave's combo, it is a track proven setup.
Needs rear gear and a great 4k+ converter to make it come to life.
Follow the recipe and it does perform very well.
http://www.youtube.com/watch?v=fn719sol8hE
#13
Launching!
iTrader: (1)
Nah dude, there is tons of 243 info on this site. You just need to search.
There are so many great running cars on this site. It just takes some patience to sit down and read through all the fluff.
bluecajun5.3 has put together a good low 10's runner, and it will just get more impressive as time progresses.
https://ls1tech.com/forums/carburete...d-mustang.html
Look at Speedtiggers setup for a quick yet street friendly combo.
https://ls1tech.com/forums/carburete...-carb-cam.html
There are so many great running cars on this site. It just takes some patience to sit down and read through all the fluff.
bluecajun5.3 has put together a good low 10's runner, and it will just get more impressive as time progresses.
https://ls1tech.com/forums/carburete...d-mustang.html
Look at Speedtiggers setup for a quick yet street friendly combo.
https://ls1tech.com/forums/carburete...-carb-cam.html
#14
On The Tree
iTrader: (2)
the mustang is more of what i am looking towards...but no head work or flycut. similar weight, and i am running a 5 speed. if i made it into the 50's or 60's i'd be happy.
sorry to jack the thread fellas, it just seemed to have the most current posts in a similar thought range. thanks a bunch for the info!
sorry to jack the thread fellas, it just seemed to have the most current posts in a similar thought range. thanks a bunch for the info!
#15
TECH Resident
The data I have shows the 243's flowing about 5% better than the 317's. So, they are in the same class along with the larger combustion chamber of the 317. I am having a hard time believing GM gave those two heads identical port volume and valve size yet altered one of them enough to gain/lose 5%. I wish one of the shops could confirm that info on back to back tests of these heads. It seems like the "production" way to do things would have been to just alter the combustion chamber size.
#18
10 Second Club
iTrader: (4)
Join Date: Jan 2004
Location: Martin Mi
Posts: 1,068
Likes: 0
Received 0 Likes
on
0 Posts
From the searching I did for my project, flycutting the pistons with the L92 heads and a carbed setup, makes the differance between a combo that moves out, and a combo that FLYS. The flycuts give you the ability to put a cam profile in that compliments the heads better. Just my .02. Eric L
#19
TECH Resident
This is my top secret source. Give me your views/thoughts.
http://www.theturboforums.com/smf/ls...swap-info-etc/
http://www.theturboforums.com/smf/ls...swap-info-etc/
#20
Teching In
iTrader: (1)
Join Date: Jun 2010
Location: Mass
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
I always pondered on the ability of making decent power with the l92's and a small cam. I know many of us don't even consider emissions, but wouldn't this combo help those that need to pass?