Modifying lq-9 with stock 317 heads

[Yenko68]

I know the LS3 heads are a great improvement cheap head for the LQ-9's but if you consider all the parts along with the intake you are looking around $1,500 - $1,800. Since I am already trying to get all of the other parts to get my 68 Camaro to run with this motor I'd rather spend the money on getting it to run 1st. I know the 317 heads can handle more cam then the stock stick but has anyone ran a better cam with the stock heads and how much power did they make? I can do a cam swap for roughly $900 and I cannot locate any comments on this. I'm hoping for an honest 430-450hp with headers, flashed ECM, an LS6 intake, and of course a cam.

[Z06vet]

You can do that no problem. A good cam, good tune, and long tubes should get you over 450 easily. The 317s flow about as well as 243's. If youre on a budget thats a good setup you have planned. Can always upgrade the heads later. Like to see you build.
Scott

[69cutlassrkt]

It would be easier to find out more about it on ls1tech. http://ls1tech.com/forums/dyno-guesses-bench-racing-forum/1536842-predictions-lq9-799-heads-eps-cam-ls6-intake-stalled-4l60e.html

[garys 68]

Exhaust and tune put you over 400hp alone. I went that route and discovered I didn't need any more hp.
http://www.hotrod.com/techarticles/engine/hrdp_0710_6l_ls_series_small_block/viewall.html#ixzz21ehbAsre

[Yenko68]

Thanks for the feedback. I'm bad about blowing the money on the parts I want instead of what I need and that is the main reason I have never driven my car. I'm tired of dumping money into this 15 year project. I need to dedicate or give it to someone that will do what I have not been able to focus on. Do any of you know if the truck intake will fit under the hood? It looks tall and I read the don't fit under some cars but if I'm going to have to take it off I'd rather swap it on a stand rather than bent over the fender.

[srh3trinity]

Believe it or not, recently I have seen some of the LS3 guys go back to a ported cathedral port head on high HP builds. Those heads out of the box were a pretty well flowing head. I am with everybody else in thinking that with a Cam and exhaust you could make great power. It helps that you have an LQ9 since they have a little more compression. On LS1tech, there should be plenty of documented builds and cam opinions for that motor.

[Yenko68]

I think I will go that route. I can always go up and it gives me a reason to make a nice build up and put it on-line for this style motor. I have had no luck so maybe I can help others into this style. I'll call COMP cams and see what cam they recommend since the HOT ROD LInk that was provided showed the flow chart.

[69cutlassrkt]

if you go with the l92 heads make sure you get a cam speced for it. Being that the bore is smaller on the lq9 than the ls3.
Heres a quote from Martin at Tick Performnace. Patrick Guerra also talked about the same thing btw.

http://ls1tech.com/forums/dynamometer-results-comparisons/1584153-low-numbers.html

"He is using a 4.0" bore, those heads were designed for a 4.065" bore. I know there will be people that argue that it is minute, but it's a big difference maker in flow at low to mid lifts. Up top in the higher lifts there is more available air mass so you don't see as much of a drop in peak air flow, but torque production suffers. Torque=HP...the more torque you can make and then shift to your advantage where you want it the more hp you will make as a result.

The large intake valve of the LS3 heads along with the large intake runner on a smaller bore with diminished low-mid lift flow numbers will not carry enough port velocity to make efficient torque production. This is why the cathedral port TFS heads make so much overall power and can make huge power up top when the torque curve is taken advantage of and shifted where the power wants to be made, intake manifold design will limit rpm that peak power is made though so the combo as a whole needs to be taken into consideration.

The large runner also does not help and needs the added air flow that a larger bore will offer.

In a nutshell this is the dilemma. Camshaft can only do so much when the short block isn't optimized to the cylinder head. You could try and throw some more intake duration at it to make the IVC event later for more peak hp, keep the ICL tight to not lose a lot of torque it has and then throw 4-6 more degrees on the exhaust duration to try and bump the mid-range and peak numbers some by helping carry the torque out further past peak torque. "

They also talk about in another thread that intake valve placement isn't as good on a 4'" bore and can cause the results to not be so great. And something how you need the right cam specs to help it do well. I don't remember exactly. I couldnt find the thread on it

EDIT: Nevermind thought you were going with ls3 heads

[Yenko68]

That was very in depth. I like the detail. I'm thinking on this round of using the 317's. With the flow chart off Hot Rod Magazine I'll call Comp Cams and find a cam that complements that head. Something that is not too large but if and when I go to the LS3 Heads it work as well. I remember in a Ligenfelter book that said a good head with a small cam will always perform better than a poor head with a huge cam. I'm trying to be realistic and since the 317 have decent flow I'd just like to step it up and find something that will go in front of my TKO 600 , power steering, and my manual brakes and my 23 bolt with 3.55 gears. I'd like to keep decent vacuum but a real healthy sound a good bottom and strong mid to upper power. I'm thinking 1st gen specs but maybe around 230 degrees area. Unfortunately , Comp has so many to chose I was hoping one of you could recommmend what you have tried