need specs on stock 97 vortec motor

[19doug90]

Had a couple questions that i didnt find in the stickies.

Firstly i have a 97 yukon gt 4x4, which set of vortec heads would have come on my car.

i found a database with headflow and it lists
L29
L31
L31 885 ccm?(ecm?)
vortec 885
http://racingfeed.com/downloads/chevy_flow_data.pdf

also wanted to find out what the specs are on the cam that would be in the motor, see how everything matches up

also would be great if i could find intake flow numbers at the lower port for the stock intake.

[airdeano]

L31 is the V8 5.7L vortec
ccm (car craft magazine)
885, 062 and 906 are casting numbers
pauly can elaborate on the camshaft profile.
sumptin' like 197/203° .397/.412 lift??
dunna know if anyone actually flowed the vortec manifold.
but thats not the short side of the system. FUEL
your injection system is like a 19lb/hr flow rate.
(305 tuned port camaro/firbirds had 19lb/hr injectors)
so fueling high horsepower can be a problem.

airdeano

[19doug90]

L31 is the V8 5.7L vortec
ccm (car craft magazine)
885, 062 and 906 are casting numbers
pauly can elaborate on the camshaft profile.
sumptin' like 197/203° .397/.412 lift??
dunna know if anyone actually flowed the vortec manifold.
but thats not the short side of the system. FUEL
your injection system is like a 19lb/hr flow rate.
(305 tuned port camaro/firbirds had 19lb/hr injectors)
so fueling high horsepower can be a problem.

airdeano

well considering the L31 flow numbers based on the link i provided probably dont start falling off until around .480 could definitly use some more lift.
At first glance i was tempted to just say it could use a bigger cam, but in the 200/200 range is probably a good amount of duration for a truck motor, make sure you have lots of power at 1100 rpms, just needs some 1.6 roller rockers and lifters i guess.

would be nice to know how much cfm the intake flow at its lower port to know how restrictive that is.

I'm new to tbi. What LB injectors are actually in the car.
And if i was going to run 1.6rr and roller lifters, those thorley tri-y headers, and probably a home made CAI cause the volant one doesnt look like anything special to me.

what lb injector for a TBI car would be ideal for this setup?

Also toying with the idea of running a scoggin dickey vortec tpi base, and running a stock tpi intake on the top half, seen a motor make 300hp 400 ft lbs on stock tpi vortec motor.

I'm not sure how i would get pulse reference for all the injectors tho out of a tbi computer, and am not looking to switch back to obd1.

[discostu]

I tried posting last night but the site got locked up so here goes...
The L31 cam is the same as the B/D body LT1 cam which has the following specs:
191/196 duration @ .050" with .418/.430" lift and 111* LSA. Hydraulic Roller lifters.

Not sure about flow on the lower intake, but I remember a few guys trying out the VMax intake spacer. It's supposedly good for +20hp and +20ft-lbs on a stock engine.

[Red376]

Kind off topic...
But what is the deal with no a/m performance intake manifolds available for the 96-00 vortecs? Hell I can't even find full length headers that fit my truck. There are some Thorley tri-y's at Summit but they state they only fit automatics.
I shoud sell it and get a 2wd obs.

sorry for the rant and thread hijack.

[ShortWideVortec]

Kind off topic...
But what is the deal with no a/m performance intake manifolds available for the 96-00 vortecs? Hell I can't even find full length headers that fit my truck. There are some Thorley tri-y's at Summit but they state they only fit automatics.
I shoud sell it and get a 2wd obs.

sorry for the rant and thread hijack.

Pacesetter makes a set, for manual trans. too I believe. Might wanna chech em out. Part number 72C2262 for ceramic.

[bored&stroked]

Vortecs are rated 239cfm @ .500". They stall at that point and drop flow until right around .600 where they are back at 239cfm or so. Its really the .200-.400" lift numbers that are the impressive part though.

[airdeano]

would be nice to know how much cfm the intake flow at its lower port to know how restrictive that is.

i know its a single plane 5.5-5.75" intake runer before the
cylinder head mating surface. if i get some time i can flow the
vortec manifold. my guess on the front four cylinders will be
excess of 400cfm per port (better than the late LSx/GENIII @
285-310cfm), but the back half will suffer as the fuel injector
body pretty much slices the manifold in half with a wall of
injector(s).
this will hopefully show the flow gain in the VMAX manifold
spacer as well.

airdeano

[19doug90]

Kind off topic...
But what is the deal with no a/m performance intake manifolds available for the 96-00 vortecs? Hell I can't even find full length headers that fit my truck. There are some Thorley tri-y's at Summit but they state they only fit automatics.
I shoud sell it and get a 2wd obs.

sorry for the rant and thread hijack.

not thread highjacking, anything about making these motors go fast in this thread is welcome. Ive got questions about all that stuff too.

191/196 duration @ .050" with .418/.430" lift and 111* LSA. Hydraulic Roller lifters.

Not sure about flow on the lower intake, but I remember a few guys trying out the VMax intake spacer. It's supposedly good for +20hp and +20ft-lbs on a stock engine.

That being said i think the cam is pretty descent for what i want out of the truck, however i think a top end rebuild of the heads. And 1.6 roller rockers and lifters will be in order. 1.6 rockers should put the engine in the perfect power range for the flow range of the head.

would consider doing some minor work to the heads, but nothing to make them flow more, just to make them flow better, if ya know what i mean.

and if you really think it would flow 400 cfm per port i take that as a really bad thing.

i dont know anything about tbi so i dont know if that changes things?? but in my camaro my stealth ram i think only flows around 275 at each port and thats almost too much volume of air for the velocity you lose.

if youre getting that much cfm at every port you are losing velocity and on a small motor velocity = tq

[Fast305]

The vortec intake is most like the old Crossfire intake and the old 2x4 manifold that Chevy sold back in the day to use on the old Z/28 302s. The runners are flat and feed the cylinders on the opposite sides. The Marine L30/L31 manifold is a very good upgrade for the ones of us that elect to dump the EGR system and need larger, external injectors. My 1998 Express van has a TPI setup on top of the Vortec 350 in it.

[bored&stroked]

and if you really think it would flow 400 cfm per port i take that as a really bad thing.

No thats a really good thing. You can have high flow and high velocity at the same time. Thats exactly what the vortec heads do. As for your TPI intake, its the runner length that changes the RPM band its working at, not the flow. Stock TPI runners are longer then a hair bands haircut and makes more torque then almost any other kind of induction out there.

That being said i think the cam is pretty descent for what i want out of the truck

Your kidding right? Its one of the lamest cams ever put in an engine. The smallest cam anyone should consider if they have a choice is the ht383/ramjet/marine cam at 196/206@.050.

[19doug90]

The smallest cam anyone should consider if they have a choice is the ht383/ramjet/marine cam at 196/206@.050.

is 197/203 not almost the exact same thing.

Not looking for an all out horsepower motor, want torque and gas mileage firstly. Then just get as much out of that top end as i can.

the cam its self could use at most 5 degrees of duration imo for what i want, and for stock heads the lift numbers with 1.6's i dont htink will be bad.

[19doug90]

The vortec intake is most like the old Crossfire intake and the old 2x4 manifold that Chevy sold back in the day to use on the old Z/28 302s. The runners are flat and feed the cylinders on the opposite sides. The Marine L30/L31 manifold is a very good upgrade for the ones of us that elect to dump the EGR system and need larger, external injectors. My 1998 Express van has a TPI setup on top of the Vortec 350 in it.

care to explain what computer system you have controlling that tpi 350?

Finding a lot of info on this site about that marine manifold swap, does look like a pretty solid platform.

[Fast305]

care to explain what computer system you have controlling that tpi 350?

Finding a lot of info on this site about that marine manifold swap, does look like a pretty solid platform.

I repinned and added a few wires to the 1997 harness in order to use, a stock 2002 Van PCM. Its a 0411 Silver Box that I reflashed to run without EGR and it runs the setup great. Running 24# LT1 injectors in a SDPC Vortec TPI base manifold, using everything else from a 1990 Camaro LB9 305 TPI. Stock TPI throttle body, stock plenum, stock TPI runners, Fuel Rail converted to rear feed to match the Express stock fuel lines, Stock TPI sensors.

The stock 1997 PCM could have been used just as easily.

[19doug90]

I repinned and added a few wires to the 1997 harness in order to use, a stock 2002 Van PCM. Its a 0411 Silver Box that I reflashed to run without EGR and it runs the setup great. Running 24# LT1 injectors in a SDPC Vortec TPI base manifold, using everything else from a 1990 Camaro LB9 305 TPI. Stock TPI throttle body, stock plenum, stock TPI runners, Fuel Rail converted to rear feed to match the Express stock fuel lines, Stock TPI sensors.

The stock 1997 PCM could have been used just as easily.

cool ill keep that in mind for down the road.

For the immediate future it looks like ill see the largest gains from those pacesetter LT's listed above and some 1.6rr's and lifters, and a bit more injector.

what size injectors are in the throttle body from stock?

[Pauly]

vortec 305/350 cam specs are 192°/197° .412"/.427" on a 111°LSA.

I like the LT$ production ca 203°/210° .446"/450" with 1.5 rockers or .476"/.480" on a 115°LSA.

Hooker Competition series 2462 HKR (painted) or 2462 1hkr (ceramic coated) will fit your Yukon, they are designed for the 88-95 TBI engines,but I am using them on my 1997 Vortec 350 truck with no issues. They have 1 5/8" primaries adn 2 1/2" collectors

The next step up is the Hooker SUPER Competition Series 2806 hkr(painted) or 2806 1hkr(ceramic coated) with 1 3/4" primaries and 3" collectors.

On either header, if you need to retain EGR you need to get an EGR feed bund welded into a primary tube on teh drivers side to feed the intake with exhaust gas. OR what I did, I got PCM tuning to disable EGR, I still pass emissions sniffer tests too.

Hedman also has a set of headers that will fit your Yukon, they even have the EGR bung allready installed.

Your engine is Vortec engine, RPO code L31, its NOT TBI, its called CSFI or central port sequential fuel injection, by calling it TB injection you make it sound like teh 88-95 TBI setup. The stock Vortec CSFI injectors are 19 pph but flow about 22.3 pph at the Vortecs fuel pressure of 60 psi. You wont run out of fuel on a Vortc 350 engine naturally aspirated. Those injectoprs are good for around 400-420hp, as per Vortec Stroker 383 Vortec engine that dynoed at 330rwhp or about 400 crank hp. He has since added a Vmaxx spacer and dropped from a 14.1 in teh 1/4 mile down to a 13.7 1/4 mile. He added 1-2 mph trap speed which indicates 15-25hp gain IMO.

The same wires that control Fast305's TPI injectors are used to run my 24 pph injectors in my L31/L30 cross ram marine intake manifold. The 1996-2000 black box PCM an dthe 411 PCM Fast305 is using use injector drivers that will run any typical high impedance injector. heck you can use a Vortec carb intake, drill injector bungs in it, fit the intake with fuel rails and fuel lines and use either PCM to run teh injectors. You can also run teh Ramjet 350 intake manifold as it fits Vortec heads. I chose the Marine intake as its a complete setup that was desiggned by GM and looks stock, and all air intakes and ALL supercharger kits designed for the Vortec 350 or 305 will bolt right up to this intake.

Heres the marine intake conversion thread(Im HOG on that forum)

http://www.pacificp.com/forum/viewtopic.php?t=317

And here is the silver 411 PCM swap thread from the same forum(this is teh Ramjet intake I was speaking of)

http://www.pacificp.com/forum/viewtopic.php?t=3240

Happy reading, it will help you undertsand all about teh Vortec 350 and its intakes shortcommings.

peace
Pauly

[19doug90]

vortec 305/350 cam specs are 192°/197° .412"/.427" on a 111°LSA.

I like the LT4*** production ca 203°/210° .446"/450" with 1.5 rockers or .476"/.480" on a 115°LSA.

Hooker Competition series 2462 HKR (painted) or 2462 1hkr (ceramic coated) will fit your Yukon, they are designed for the 88-95 TBI engines,but I am using them on my 1997 Vortec 350 truck with no issues. They have 1 5/8" primaries adn 2 1/2" collectors

Pauly

Ya that cam sounds absolutly perfect, at some point this 350 is going to get freshened, stock bottom end rebuild with good bearings and probably hyper pistons.

want to keep gas mileage so wouldnt run anything over 203/210 thats like max rpm i want to pull. And at .48 lift with 1.6's i dont think youd even need to touch the stock heads cause thats probably around where they flow up until.

im gonna check if comp cams actually has an xfi cam or something that has around .50-.51 lift so i have an excuse to port the heads a little.

I'm in love with hooker long tubes, 1 5/8ths will support 400 hp making gobs of tq, only going to run 2.5" duals on this truck anyway way more torque. If not also way more space and better fuel economy. Very glad to know that works, ill end up buying a set of those probably just painted.

as far as intakes i wouldnt run a ranjet for the simple fact thats a horsepower intake, i want to have this truck make as much power at 1000 rpms as possible.

i really dont know what to do here because in the long run i want to do a TPI swap, but tpi isnt exactly the most fuel efficient intake to get you from point A to B and this is my DD for a while. I found crazy links on this board already on the marine intake toons of reading to do all of which i am procrastinating from seeing as how im fresh off learning obd1 stuff and my brain still feels like mush

[discostu]

And at .48 lift with 1.6's i dont think youd even need to touch the stock heads cause thats probably around where they flow up until.

im gonna check if comp cams actually has an xfi cam or something that has around .50-.51 lift so i have an excuse to port the heads a little.

To get stock Vortec heads over .480 lift, you need to do some modifications or get a different set of springs and retainers (Comp 981's come to mind) that will increase your lift potential to .525 or so.

[19doug90]

To get stock Vortec heads over .480 lift, you need to do some modifications or get a different set of springs and retainers (Comp 981's come to mind) that will increase your lift potential to .525 or so.

ya...we'll see, i would have to look into what sort of porting the heads respond best to. I just like to dream big.

Realistically that LT4 cam seems like it would optimize the stock heads perfectly.

EDIT: okay theres no way this is right
http://store.summitracing.com/partde...5&autoview=sku

200 bucks for the pair.... i payed 700 for the camaro ones. The real question is how can i afford NOT to buy these

EDIT #2 : vortec motors have oval ports? does that matter? and why is the o2 bung welded on one of the tubes not the collector in the pic?

[Pauly]

ya...we'll see, i would have to look into what sort of porting the heads respond best to. I just like to dream big.

Realistically that LT4 cam seems like it would optimize the stock heads perfectly.

EDIT: okay theres no way this is right
http://store.summitracing.com/partde...5&autoview=sku

200 bucks for the pair.... i payed 700 for the camaro ones. The real question is how can i afford NOT to buy these

EDIT #2 : vortec motors have oval ports? does that matter? and why is the o2 bung welded on one of the tubes not the collector in the pic?

That price is right, they are $200 uncoated or $400 for ceramic coating. These headers are teh Competition series from Hooker, teh S series for our trucks are $400 pianted and 4750 coated, those are teh that have teh 1 3/4 x3" tubes although tehy are made of thinner 18ga tubing.

The is weld3ed in acollector because these headers are designed for the 88-95 TBI engines and thats where the O2 sensor is. I had my O2 sensor byngs wellded in my headpipes just after the collectors so I didnt disturb my cermic coating headers.

I dont think I had any port alignment issues.IIRC

peace
Pauly