what cam for 418 stroker with prc 237 heads
#24
FormerVendor
iTrader: (3)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
From what you've described, I would suggest a custom grind. Something similar to these:
239/246 .624"/.595" 114lsa
243/248 .624"/.595" 113lsa
If you want the best drivability possible with the ability to make 500rwhp the 239/246 114lsa profile would be my choice.
If you want to sacrifice some drivability with the ability to make more than 500rwhp the 243/248 113lsa profile would be my choice.
I wouldn't use the Emissions cam or Stage 2 LS7 cam in this application.
239/246 .624"/.595" 114lsa
243/248 .624"/.595" 113lsa
If you want the best drivability possible with the ability to make 500rwhp the 239/246 114lsa profile would be my choice.
If you want to sacrifice some drivability with the ability to make more than 500rwhp the 243/248 113lsa profile would be my choice.
I wouldn't use the Emissions cam or Stage 2 LS7 cam in this application.
#25
On The Tree
iTrader: (4)
Join Date: Jun 2002
Location: Los Angeles
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
From what you've described, I would suggest a custom grind. Something similar to these:
239/246 .624"/.595" 114lsa
243/248 .624"/.595" 113lsa
If you want the best drivability possible with the ability to make 500rwhp the 239/246 114lsa profile would be my choice.
If you want to sacrifice some drivability with the ability to make more than 500rwhp the 243/248 113lsa profile would be my choice.
I wouldn't use the Emissions cam or Stage 2 LS7 cam in this application.
239/246 .624"/.595" 114lsa
243/248 .624"/.595" 113lsa
If you want the best drivability possible with the ability to make 500rwhp the 239/246 114lsa profile would be my choice.
If you want to sacrifice some drivability with the ability to make more than 500rwhp the 243/248 113lsa profile would be my choice.
I wouldn't use the Emissions cam or Stage 2 LS7 cam in this application.
#26
FormerVendor
iTrader: (3)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
In my opinion it comes down to lobe selection and selecting the proper valve events at different lift intervals as to why I specify my cams with less exhaust lift. I also prefer a milder exhaust lobe which normally a milder lobe has less lift. Not always, but most of the time.
I don't feel exhaust lift is nearly as important(it's still important) as intake lift since the exhaust lobes job is not to fill the cylinder.
Exhaust is pressurized at a very high PSI. Much more so than the intake charge. Because of this it does not need as much lift to clear the cylinder as the intake lobe does to fill the cylinder.
Two totally different roles.
I don't feel exhaust lift is nearly as important(it's still important) as intake lift since the exhaust lobes job is not to fill the cylinder.
Exhaust is pressurized at a very high PSI. Much more so than the intake charge. Because of this it does not need as much lift to clear the cylinder as the intake lobe does to fill the cylinder.
Two totally different roles.
Last edited by Sales@Tick; 11-27-2013 at 07:08 PM.
#29
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
thanks a bunch Martin, you've been a great help and very quick to reply to all my questions, I'm gonna go with the 247/250 .624/.595 114+4 cam you recommended... I'll be sure to post the results after
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
#31
FormerVendor
iTrader: (3)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I would expect your slightly larger engine and slightly larger heads even with a more docile cam to make similar power.
#32
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
that would be great!!!! although i feel i have a huge drivetrain loss even with a six speed. my stock ls6 put down just 300 hp on a dynojet in fl once. but it did manage 320 with a cai untuned.... but taking into account c5 zo6s have made 360 stock i'm gonna be etremely happy to get above 500 even if just a little, the setup i have now is a ls6 with cnc ported and extremely decked 317s that i had to shave down the underbelly of my ls6 intake before going to my fast to get it to fit. the ls6 intake would rock on the heads they are decked so much.... i'm actually not sure what my comp ratio is on the current motor... the cyl pressure is 235 in each cyl in a comp test and i have been told that it is 13.5 by one shop, but since they are 317s i find that hard to believe considering the cam i'm running even taking into account the people who put the cam in told me i'll have marks on the pistons afterwards.... even with this setup the car only makes 430rwhp, the 455 in the sig was a cold run fluke so i'm really looking forward to the results of the cam you rec'd
#33
On The Tree
iTrader: (4)
Join Date: Jun 2002
Location: Los Angeles
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
martin how do these prc heads flow compared to ported stock ls3 head? if i had 823 heads which are ported would i gain noticible rwhp/tq by switching heads ? or are 821s good enough?
#35
On The Tree
iTrader: (4)
Join Date: Jun 2002
Location: Los Angeles
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
and to verify the small bore ls7 heads flow the best out of all 3 right, make the most power?
#36
FormerVendor
iTrader: (3)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
I could honestly care less about flow numbers and using that to determine how much power a certain cylinder head is capable of producing. I'm much more concerned with port volume, cross sectional area and valve diameter/area. Much more so than how high can a company inflate their flow numbers using test parameters that will never be seen in the real world.
#37
On The Tree
iTrader: (4)
Join Date: Jun 2002
Location: Los Angeles
Posts: 175
Likes: 0
Received 0 Likes
on
0 Posts
![](https://ls1tech.com/forums/images/ranks/ls1tech10year.png)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I never said they flow better. ![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
I could honestly care less about flow numbers and using that to determine how much power a certain cylinder head is capable of producing. I'm much more concerned with port volume, cross sectional area and valve diameter/area. Much more so than how high can a company inflate their flow numbers using test parameters that will never be seen in the real world.
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
I could honestly care less about flow numbers and using that to determine how much power a certain cylinder head is capable of producing. I'm much more concerned with port volume, cross sectional area and valve diameter/area. Much more so than how high can a company inflate their flow numbers using test parameters that will never be seen in the real world.
#38
FormerVendor
iTrader: (3)
![Default](https://ls1tech.com/forums/images/icons/icon1.gif)
I wouldn't use a small bore LS7 head unless the bore was 4.030" or larger and preferably 4.065" and larger.
You have to look at the port volume and valve diameter versus the operating range of your engine.
IMO there is no need for such a large port/valve combination on an engine that cannot turn more than 6500-7000rpm while efficiently producing power.