317 Heads Question
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
317 Heads Question
I just bought a set of 317 heads with the idea of doing a cheap H/C setup for my procharged c5. They are completely stock including springs and everything. My question is are the springs capable of being used with a 2002 stock zo6 cam. Also what kind of power gains might I expect from this conversion running the same boost level. Thanks for the answers in advance.
Burning Brakes
Joined: Nov 2004
Posts: 822
Likes: 0
From: Grafton Ohio
I would change the valve springs while the heads are off the car. Comp 918's are easy enough to do.
As far as power goes here's some comparisons. I have a 98 with 317 heads, Patriot gold dual valvesprings, cartek 2x cam and a procharger. With 10 psi 19 degrees total timing and 93 octane I make 592/527.
My buddies 03 z06 all stock except longtubes and vortech 13 degrees total timing and 8 psi he's at 550 rwhp with meth not sure of tq numbers.
The 317 heads are a great way of lowering compression and allowing you to run more boost which in turn equals more hp/tq.
Jer.
As far as power goes here's some comparisons. I have a 98 with 317 heads, Patriot gold dual valvesprings, cartek 2x cam and a procharger. With 10 psi 19 degrees total timing and 93 octane I make 592/527.
My buddies 03 z06 all stock except longtubes and vortech 13 degrees total timing and 8 psi he's at 550 rwhp with meth not sure of tq numbers.
The 317 heads are a great way of lowering compression and allowing you to run more boost which in turn equals more hp/tq.
Jer.
Safety Car
Joined: May 2002
Posts: 3,615
Likes: 2
From: waterloo ontario
St. Jude Donor '08
The heads will really shine above 10 psi. I would upgrade the springs to a good dual while there off the car and get the chambers CNC'd to insure there 72cc and no more.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Originally Posted by eb02z06
The heads will really shine above 10 psi. I would upgrade the springs to a good dual while there off the car and get the chambers CNC'd to insure there 72cc and no more.
Drifting
Joined: Jan 2002
Posts: 1,731
Likes: 1
From: Bay Area CA
You should be fine with the stock springs for 550rwhp. You'll need to run more boost to make the same power as you are now due to the lower compression. If it were me, I would do the springs while the heads are off. I wouldn't bother with a Z06 cam either for only 550rwhp. Good luck.
Advanced
Joined: Sep 2006
Posts: 97
Likes: 3
From: Anniston Alabama
Originally Posted by jers98vet
I would change the valve springs while the heads are off the car. Comp 918's are easy enough to do.
As far as power goes here's some comparisons. I have a 98 with 317 heads, Patriot gold dual valvesprings, cartek 2x cam and a procharger. With 10 psi 19 degrees total timing and 93 octane I make 592/527.
My buddies 03 z06 all stock except longtubes and vortech 13 degrees total timing and 8 psi he's at 550 rwhp with meth not sure of tq numbers.
The 317 heads are a great way of lowering compression and allowing you to run more boost which in turn equals more hp/tq.
Jer.
As far as power goes here's some comparisons. I have a 98 with 317 heads, Patriot gold dual valvesprings, cartek 2x cam and a procharger. With 10 psi 19 degrees total timing and 93 octane I make 592/527.
My buddies 03 z06 all stock except longtubes and vortech 13 degrees total timing and 8 psi he's at 550 rwhp with meth not sure of tq numbers.
The 317 heads are a great way of lowering compression and allowing you to run more boost which in turn equals more hp/tq.
Jer.
Thread Starter
Burning Brakes
Joined: Feb 2006
Posts: 844
Likes: 46
From: Southaven MS
Originally Posted by Ramsiec5
This is safe with stock bottom-end?
Burning Brakes
Joined: Nov 2004
Posts: 822
Likes: 0
From: Grafton Ohio
Originally Posted by Ramsiec5
This is safe with stock bottom-end?
I remember when 500rwhp was pushing the limit. Then it was (is) 550 rwhp. I've been running my stock shortblock hard for 4 years now from nitrous to an ATI P1 and now an ECS D1 for the last 2 years.
I intend to keep pushing the envelope till it pops then go forged and be done with it.
Jer.
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Burning Brakes
Joined: May 2003
Posts: 1,058
Likes: 0
From: Roswell New Mexico
St. Jude Donor '07-'08
you don't need to have the heads cnc'd, but you DO need to change the springs. The ls1 springs are barley adequate for the lift of the stock cam. 02 Z's have a .550 lift and the 01 are a .535 you are begging for float or a broken spring.
you need to change springs!!
you need to change springs!!
Burning Brakes
Joined: Nov 2004
Posts: 822
Likes: 0
From: Grafton Ohio
Originally Posted by easyvette
Sorry guys I cant figure out what the compression would be on an LS1 motor with 317 heads. Figuring all the head gaskets are OEM thickness?
I`m guessing 9.5:1??????
I`m guessing 9.5:1??????
My static CR came out to 9.62:1. Check out this link, it helps out when figuring out your CR.
http://www.rosspistons.com/calculator.php
Jer.
Burning Brakes
Joined: Aug 2006
Posts: 901
Likes: 1
From: Oxford PA
Sorry gotta keep hyjacking this thread. Lets talk valve sizes on 317 heads. Is it better to go with the larger 1.60 and 2.05valves or stay with the 1.57 and 2.02 valves? My guess would be bigger valves will flow better however I think the smaller valves will help with boost. Looking for any info. Thanks
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
Originally Posted by jers98vet
I would change the valve springs while the heads are off the car. Comp 918's are easy enough to do.
As far as power goes here's some comparisons. I have a 98 with 317 heads, Patriot gold dual valvesprings, cartek 2x cam and a procharger. With 10 psi 19 degrees total timing and 93 octane I make 592/527.
My buddies 03 z06 all stock except longtubes and vortech 13 degrees total timing and 8 psi he's at 550 rwhp with meth not sure of tq numbers.
The 317 heads are a great way of lowering compression and allowing you to run more boost which in turn equals more hp/tq.
Jer.
As far as power goes here's some comparisons. I have a 98 with 317 heads, Patriot gold dual valvesprings, cartek 2x cam and a procharger. With 10 psi 19 degrees total timing and 93 octane I make 592/527.
My buddies 03 z06 all stock except longtubes and vortech 13 degrees total timing and 8 psi he's at 550 rwhp with meth not sure of tq numbers.
The 317 heads are a great way of lowering compression and allowing you to run more boost which in turn equals more hp/tq.
Jer.
Put on 918 springs if your sticking with the stock cam b/c duals will be overkill and will make your drivetrain heavier than it needs to be. The 918s are the perfect replacement spring for you and since your going to be boosted the 918s will be good cheap insurance and piece of mind to replace the used springs on the used 317 heads (I assume the heads are used).For your power goals get a professional install and tune, and run 10 to 11lbs of boost with the 317 heads and you will make your goal easily and no reason to change anything except add HARDENED PUSH RODS also if you swap out out to the 918s or any other replacement springs!
I did A LOT OF RESEARCH on what was the PERFECT replacement spring for my stock LS6 motor and the 918s are what 90% of of seveal TOP TUNERS recommended for me b/c of the lightness of the spring and since it is a direct replacement for stock ls1/6 springs and I have had 4000 trouble free miles with the 918s on my blown 100% stock LS6 motor.
Last edited by Mopar Jimmy; Dec 8, 2006 at 11:15 PM.
