Old Vortec Camshaft POLL!!!

speedshifter · April 7, 2004

Hey guys,

I'm tired of making my own mistakes. I need to get a good cam in this thing and I'm not doing any tuning to the ECM so I want something that runs strong on a factory tune. I have the comp cam now (#08-411-8) that is too big and surges like a mutha at stop lights. Gas mileage is terrible and so is my low end powerband.

Okay here are the candidates:

And for the hell of it, lets throw in this GM performance parts cam:

10185071 Hydraulic Roller Tappet

This hydraulic roller tappet is used on the 5.7-liter H.O. 350 ZZ3 & 4 engines. The duration at lash point in degrees (intake/exhaust) is 275/280; duration at .050" tappet lift (intake/exhaust) is 208/221; and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 474/501. Valve lash is zero/zero and lobe centerline is 112 degrees.

The specs on this GM cam look real close the the other cams on the poll, and it will cost me a fraction of what the other cams will cost because I work at a GM dealership and get really good discounts.

Take a look at what there is to choose from and help me out. This will decide what cam I use, and will help many others who have the same motor, but dont want to take the chance of doing the wrong cam like I did.

Thanks!

Wingnut · April 7, 2004

I would say start w/the GM cam. Just for the price.

If you aren't happy with that....I prefer Lunati, but that's only personal preferance.

Curious, but why not get a tune with it?

speedshifter · April 7, 2004

I like my superchips tuner because of the adjustability. Custom tunes to me cost too much and can have bad results. Not to mention the downtime involved with sending out the ecm.

I just want some better gas mileage and crazy torque, thats all I ask. I know its not a camaro, but i mean what the hell, a man needs to lite up the tires on his truck now and then.

I guess if I still have problems after the next cam, I'll be forced to have it tuned. I need a different cam no matter what tho because this thing just has no torque.

I mean I raced against my cousins tahoe who has a k&n, and a full exhaust and he beat me by a 1/2 car length. For all the money and time I have into this thing, I'm pretty disappointed with it.

I do have a 6.0L escalade 345hp motor laying in the back at work. Maybe if I get super bored and get a harness, ecm, and trans ... nah, I'm gonna stop right there before I get myself in deeper than I already am.

99Silver6.0 · April 7, 2004

If your referring to that GM Hotcam. Id stay away from it. That thing is a tuning nightmare!

speedshifter · April 8, 2004

Yeah after sitting down and comparing the #'s on these cams to stock, the GMPP one is out of the picture. So is the Lunati.

Here are the specs on the stock cam:

Duration @ .050in

-Intake: 191 deg

-Exhaust: 196 deg

Lift w/stock 1.5 rocker:

-Intake: 0.414"

-Exhaust: 0.429"

Lobe separation angle: 110 deg

I'm looking at the specs that my cam is now and I'm boggled that I did not see this before. I'm running 19 deg int/18 deg exh more duration than the stock cam and .060" int/.045" exh more lift than stock. Those are crazy #'s!

So I'm thinking either comp, crower, or isky. Keep in mind on the crower specs that they used a 1.6 rocker and I have a 1.5 so they int/exh lift @valve should be .456"/.474". However, I have had bad experience with Comp cams, since they misled me the first time so I would be more inclined to buy from Crower or Isky.

The Isky says good from 1200-5000rpm, while the Crower says from 1900-5000rpm. They have the same intake duration at 204 deg, but the crower has an extra 3 deg of duration over the Isky at 212 deg. The crower also has slightly more lift than the Isky @ .456"/.474" vs. .450"/.465".

Hmm, I'm still leaning towards Crower...

augiedog77 · April 12, 2004

not sure what cam you should use (might get the same one if it works ok) but with a Wester's tune he sends you a new PCM. no down time and it's far superior to the hypertech (not sure about the superchips, changed from the hypertech)

Gerry

speedshifter · April 12, 2004

well i didnt know that about the westers tune. now i will look into that further once i replace the cam and see how it is.

right now tho i need to get rid of this cam cuz its not streetable for everyday driving. i have to drive two footed so that i can brake torque it slightly at idle to keep the truck from surging. it works, but its a pain in the ass.

i think im going crower for over isky due to more exhaust lift and duration which should make for a cleaner chamber when new fuel/air comes in. all opposed, voice your thoughts now, or forever hold your peace!

thanks dudes!

dfarr · July 12, 2004

i'm somewhat in the same boat but worse because my vortec is in a 89 k1500 using edelbrocks mpi and the old computer. the cam was left up to the engine builder who i assume still thinks in carb terms and didn't understand that my map needs tons of vacume. the engine ran very strong past 6000rpm but idled rough and cold starts were way rich a superchip didn't help much, changed to a stock vortec and it runs ok pretty strong, have heard good things about the LT1 z28 cam and got hold of a used one, have been told they work very well on tbi based systems. besides i can't bring myself to spend big bucks on these rollers with my luck so far.

cam1 regrind 207 210 450 459 @112

cam2 l31 192 196 415 428 @111

cam3 lt1 204 210 449 460 @117

better to go a little conservative than lose that vacume.

dfarr · July 12, 2004

check out engle cams

airdeano · July 12, 2004

Hey guys,

I'm tired of making my own mistakes. I need to get a good cam in this thing and I'm not doing any tuning to the ECM so I want something that runs strong on a factory tune.

call the camshaft manufacturers...

all you need is someone else to spend your money too....

no PCM tuning will limit your choices.

surging at idle usually is a tell-tale of too much timing and an overly rich mixture

and low MAP signal.

the 08-411-8 .474/.474 204/214° 111LSA shouldnt have too much lope or vacuum

load. you may want to have the CKP RETARD check to see if its set correctly.

if you think you camsfat is too large, all your alternatives will have worse effects

without tuning.

instead for spending more money for camshafts... tune what you have.

re-gap plugs to .052"

set CKP RETARD to 0°

tune the computer

airdeano

snoman · July 12, 2004

IF you do not want a custom tune, you better stay mild with cam as you do not want to change idle vacum too much. I would suggest a little more lift than stock without too much change in duration as without a custom tune it can be a real can of worms if you install the wrong cam. (even with a custom tune it can be challenging if cam is warm enough. this was the nice thing about old carbed engines, they were easy to adapt to this)

Tucson_02Silverado · July 12, 2004

You left out the LT "Hot" cam with 1.6 roller rockers.

It's now called the LT4 Hot cam.

12480002 350 Hot Cam Kit $580 (partszoneonline.com)

Several performance magazine articles of a couple years past using it with the L31 heads as your 97 has.

From GMPP catalog

12480002 350 Hot Cam Kit

This off-highway camshaft kit has the major valve train component to convert production LT1 engine for showroom stock racing, or hop up your small block Chevrolet V8 that was originally equipped with a roller tappet camshaft. The 1.6 roller rockers, light weight valve spring caps, special designed valve springs and hot camshaft offers a significant gain in horsepower at a reasonable price. This kit includes the following items: one camshaft P/N 24502586, 16 roller rocker arms kit P/N 12370839, 16 valve springs P/N 12551483, 16 valve caps P/N 10212808, 16 valve keys P/N 24503856, 16 valve spring shims P/N 10212809.

Technical Notes: This kit does not include roller tappets. See valve lifter section 0.459 for the lifter kit.

24502586 Hydraulic Roller (LT4 Hot Cam)

This hydraulic roller cam is for service only for all V8 engines with roller camshafts. The duration at lash point in degrees (intake/exhaust) is 279/287; duration at .050" tappet lift (intake/exhaust) is 218/228; and maximum lift with 1.6 rocker ratio (intake/exhaust) is 525/525. Valve lash is zero/zero and lobe centerline is 112 degrees.

Technical Notes: The LT4 camshaft P/N 24502586 was designed to be used in a number of different engines. Therefore, the following change may need to be made to allow for correct assembly of the engine: For LT1 and L98 engines 1995 and before, the dowel pin in the end of the camshaft must be pushed in so extension from end of cam is .30+/-.01", the same as the production part. For 1996 LT1 and LT4 engines, the dowel pin is in the correct position, extending .620" from the end of the camshaft. This camshaft has a fuel pump lobe.