Whos's done a cam only with the stock low compression 317's and how's it run? What cam are you guys running and any problems with the lower DCR?

I've got a LQ4 with stock untouched 317 heads, ls6 intake, slp lid, 85 maf, Ported stock TB, Pacesetter 1 3/4, ory dumped w/powerstick muffler, 6spd 10 bolt 3.42 gear. Frost tuned it put down 326/352 on a Mustang dyno.

I've been playing around with the PianoProdigy calculator specing some different cams and seeing what i come up with. I still don't fully grasp the concept of all the valve events and how they interact with each other so any cam gurus if you could point me in the right direction i would really appreciate it. I've been doing this to calculate a rough DCR and see if it would be worth it with these heads.

I want to leave these heads on strictly for a "budget build" If i pick up a used set of 243's and do a valve job, mill them for a little added compression i'm probably looking at roughly another $800-1k so i would rather not go down that road yet. I want a cam that's going to put me close to 400rwhp, be able to work good with the 3.42 gear for now, and pull hard from 2500-6000.

Sorry for the long post guys, thanks for reading

Here's a few cams i spec'd let me know what you think.


XER 230/234 .592/.598 111+4
IVO> 8
IVC >42
EVO>52
EVC>2
ECL>115
OVLP> 10
DCR>7.52:1

“EL Toro” XFI 230/XER 230 .612/.592 111+2
IVO>6
IVC>44
EVO>48
EVC>2
ECL>113
OVLP>8
DCR>7.37:1

LSL 227/235 .614/.621 110+1
IVO>4.5
IVC>42.5
EVO>48.5
EVC>6.5
ECL>111
OVLP>11
DCR>7.46:1

 

You can pull the heads and mill them .050 to give stock ls1 compression ratio for about $300. If your already doing the cam and valvetrain it makes much more sense to do it at the same time. Call a shop like EPS, Texas-Speed, or Thunder Racing and they can likely steer you in the right direction. 317 heads are supposed to flow about the same as 243's so that would be a much better budget way to go.

 

I know i could pull these off and have them milled a bit and run a thinner headgasket to bump compression but that doesn't really make sense to me because if i'm going to pull the heads then i'm gonna want to have them worked a bit to squeeze out some more horsepower, then it's gonna be well the heads are flowing real well now so it's time for a fast 102, etc, etc, you guys know how the modding begins to snowball out of control real quick. So to me that kind of still negates the whole "budget build"

Here's how i'm looking at it
Cam Kit-$700
LS2 Chain-$45
Tuning-$500
Engine has 65k on it and it's not going to see long extended times of high rpm so i'm going to run stock lifters and oil pump

If i can put $1200 into it and make 400rwhp i will be happy with that and i believe it will satisfy me for a couple of years until i have the funds to do my 408.

 

Lots of people on here have run stock unported heads and hit into low 11's and 10's. To get 400 whp with lower than stock compression might not be possible unless you go really large with the cam. Your asking for about 75 whp from just a cam swap which is a lot.

 

I know a lot of people are running strong numbers with the ls1 on stock 241 heads but they are around 8.0:1 DCR and a bit more if running the 243 heads. Some of my combos have me showing as low as 7.3:1, how much is that going to affect my performance? Is it going to make it really soft/sluggish on the bottom end? From everything i've read it seems you would really want to be at least 7.5:1. I'm not educated enough on this subject to really know the answer.

As far as numbers i would like to think it would make 340 on a dynojet, but we all know how dyno numbers go. My previous car was a H/C/I that made 440rwhp with a g5x3 and even with a 4.10 gear it still didn't really wake up till about 3800rpm. I want something a little smaller this go round, this car is fun to drive as is but i think a nice cam would really wake it up. So if i could gain 45-50rwhp with the cam swap i would be happy.

 

Your asking for alot on the small of a budget unless you want to spray it and make close to those numbers.Im doing my lq4 swap this week and its stock..just doin a 228r cam,7.4 pushrods and pac 1218 springs,ls6 intake,85mm maf for now.If that hits 350rwhp and over 360rwtq Ill be happy.Then later on mill the heads down and do headers and tunes should get about 390rwhp.

 

Assuming a 3% increase from going from a static compression of 9.5:1(LQ4) to 10.5:1 which would be a ls1 running stock 243 heads i get 12hp assuming the car is making 400hp. With any of the cams i'm looking at a 243 headed m6 ls1 car should be able to attain that with the bolt-ons that i already have. So theoretically i would think i should be able to pull in the 380's, i also have 18 more ci. than a ls1 as well.

I have searched a lot and haven't found any numbers for a lq4 with stock 317 heads. Lots of good info on cam choices for the 6.0 litre engines but they are all running different heads or have milled and changed head gasket to some degree. If anybody has run a setup like mine please post up your experiences.

Now can you use the same 3% while trying to calculate a one point increase in DCR or does it not work that way?

 

Anybody else running the stock 317 heads with a aftermarket cam?

 

This doesn't really make sense, you say you're on a budget but if faced with a pair of heads off the engine you're immediately going to dump a whole bunch of money on them? What's wrong with pulling them off, milling them only and gaining a whole buncha power on the budget? What's forcing you to get them worked thus breaking your budget?

I think a 9.5:1 non FI engine is going to be a dog down low, even with a cam.

 

Just stroke it out to 408 with flat tops and run the 317's. That will bump the compresion up. If I ever get my hands on an LQ4 thats what I plan to do.

 

That's the perfect advice to give someone who just said that an extra $800 going into this build is too much for his budget. Sure...recommend a $4000 upgrade to someone that can't afford $800.

 

Nothing's wrong with pulling them off and milling but if the 317's heads come off it makes sense to go ahead and put 243's on it. If i mill the 317's .030 that should put them at about a 67cc chamber and then if i run a .040 gasket i'm still only gonna be at 10.2:1. Again using the 3% per point of compression going from 9.5:1 to 10.2:1 is not going to gain "a whole buncha power" and now i am also tighter on ptv clearance.

The car is 9.5:1 now and it is not a dog down low. So back to the original point of the thread can anybody shed any light on how it would run with a DCR of 7.3-7.6:1. What kind of valve events would work well for the motor?

 

Hopefully i can afford to do that in a few years, but there's a lot of other supporting mods that will be going along with the 408, and it will definately be over 4k.

 

I think the only way to know how its going to run is to do it. It does not necessarily make a lot of sense to just say it needs 243's. The 317 heads flow about the same as 243's and if you mill them you should not need to be worried about ptv clearance unless you go with a real large cam. If you are going to go through putting a new valvetrain on your 317 heads it is not much more labor to just pull them and install the springs with the heads off the car.

 

I will be running the stock lq4 with just cam..and stock manifolds soon and will be able to give feedback on how well it performs over having my stock ls1.I do agree that you shouldnt have to worry alot about ptv if you mill the stock 317 heads for a slight bump in compression as long as your not going too large of a cam.This is why I choose the 228r cam.With the mods you already have..I think you will be just around 380rwhp with good tuning.Even with the 9.5:1 lq4 is no slouch on the bottom end with it producing torque down low and strong midrange power.I see alot of guys running lq4's here but most are heavily modded so thats why finding numbers on budget combos is hard to do.Im in the same boat and doing even more budget friendly build.Im chasing down torqe more than rwhp though.I think staying with the 317 heads..have them milled,a cam around 226-230's range with ls6 intake and decent exhaust should be competent for your current needs with out breaking the bank.With your gearing should be a nice lil toy both street and hwy.

Then later when funds are more available..you can build the motor further,change pistons,fast intake,bigger headers,port the heads or go fully aftermarket and keep the cam and you will see over 400rwhp.

 

Looking forward to hearing how it turns out, good luck

 

Thanks,I am too.Curious to see how it sounds..runs on stock ls1 tune till i get it on the rollers and tuned.Ill be sure to report here my opinion on it when its up and running.

 

buddy of mine tuned a lq4/th400 setup with a stock truck intake, LT's and a 224/224 cam from tsp and its made 370rwhp on a dynojet fwiw

 

Do you know if that was with the stock 317 heads? Thanks for sharing

 

i believe so, ill see if i can get ahold of him and find out for sure