Head flow for engine size 427-482
06-07-2012, 03:45 PM
#1
Head flow for engine size 427-482
What's the difference in power bands between the cathedral heads and the square port heads of like the l92? I know the l92's flow more out of the box but besides just flow.
Ive been doing some reading and I see some guys still use the old 317 style heads something about better mid range torque. Now if that is the case or say you do use a 317/ls6 head can a turbo make up for the lost flow in an effecient manner?
If you had a ls6 head that flows say 330-340 cfm on a 427-482ci motor and twin turbos how much power could be had by going to a set of l92 heads flowin 350-360cfm? And WOULD there be a loss in low-mid range torque? And just to keep things even and to keep out the intake manifold options just say it has a Holley hi ram on both sets of heads.
I'm just trying to learn stuff for the bigger ci motors is all.
Ive been doing some reading and I see some guys still use the old 317 style heads something about better mid range torque. Now if that is the case or say you do use a 317/ls6 head can a turbo make up for the lost flow in an effecient manner?
If you had a ls6 head that flows say 330-340 cfm on a 427-482ci motor and twin turbos how much power could be had by going to a set of l92 heads flowin 350-360cfm? And WOULD there be a loss in low-mid range torque? And just to keep things even and to keep out the intake manifold options just say it has a Holley hi ram on both sets of heads.
I'm just trying to learn stuff for the bigger ci motors is all.
06-09-2012, 11:42 PM
#2
There was an article in GM High Tech recently comparing worked mast 317 heads and worked mast L92 heads. Even though the flow numbers for the L92 heads were higher, there was virtually no difference in dyno power with the cathedrals actually winning slightly. However, the the valve lift was only around 0.600", and they mentioned if it was increased to the 0.650" range then the L92s would have done much better. This is a product of the larger valves and piston shrouding of the L92s.
20cfm on the intake side is significant, but especially in turbo applications you need a hell of an exhaust side flow to see a real difference.
20cfm on the intake side is significant, but especially in turbo applications you need a hell of an exhaust side flow to see a real difference.
06-10-2012, 03:11 PM
#6
the assembled short block is 9900. which is not bad considering what all you get. cam is also included.
i found that article. funny thing is, the cathedral heads performed just like the guy on tech was saying. a lot more low end torque compared to the ls3/l92 heads.
i found that article. funny thing is, the cathedral heads performed just like the guy on tech was saying. a lot more low end torque compared to the ls3/l92 heads.
Thread
Thread Starter
Forum
Replies
Last Post
