Vortec Head Question???!!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevjayfsd · 10-24-2002, 10:47 PM

Can anyone tell me what the biggest cam you can run in the vortec heads. I have a 350 w/vortec heads and my cam recently went flat and i am replacing it...Can someone do some research(I wouldn't know the 1st place to start looking). I have a .454 lift in it right now and i have heard you can go bigger...
Thanks
Jason

Hooter · 10-24-2002, 10:55 PM

why do cams go flat? do the lifters hang up?

**truckster** · 10-24-2002, 11:21 PM

The factory specs for the vortec say .5 inch lift max with the stock springs.

bigjimzlll · 10-24-2002, 11:23 PM

this gets a little quirky...most publications say dont go over .460 lift...then ever one says the 350 ramjet has .480 lift with vortecs. Then I read never go over .450 ever(with out the spring upgrade). My suggestion...go with the spring upgrade to be safe.
Jim

Longhorn Man · 10-24-2002, 11:24 PM

Having never read any GM papers on them, I am going by what all the magazines say...
.480 due to the lighter spring pressure.

crazy longhorn · 10-24-2002, 11:25 PM

I dont believe you can run that much lift with stock springs on the vortecs.......I think it was in the .460-.470 range.

crazy longhorn · 10-25-2002, 12:08 AM

Scoggin-dickey has som info, If i can get the page up.... it sounds like to about .450 lift. http://www.sdpc2000.com/cart.asp?act...art&catid=2172

Project1970 · 10-25-2002, 03:45 AM

I'd say whatever cam they spec in the RamJet is probably as big as you can get. The 350HO 330hp engine uses one in the low .450's...

FWIW, messing around with Desktop Dyno, the Comp Cams XE256H seemed to work really well. WIIIIDE torque curve, and lots of it.

Blazer1970 · 10-25-2002, 07:42 AM

It's easy enough to check for coil bind when you assemble the engine. I have heard it is close to .500.

Fred T · 10-25-2002, 08:50 AM

Quote:

Originally posted by Hooter
why do cams go flat? do the lifters hang up?

Cams can go flat from a lack of lube, improper break-in (run at 2,000 rpm for 20 minutes immediately), dirty oil or the big one, lifters adjusted to tight or springs that are to stiff. Throw in failure of other parts, such as a stuck valve and it's a wonder they don't go flat more often.

chevyracing · 10-25-2002, 10:23 AM

If you run more than a 465 lift you need to have the heads machined for clearance on the valve guides. It runs about 25 bucks a head to do this to. Scogin sells a set of heads that already have the machining done for an aditional charge, I am not sure but I think they run about 30 bucks more than the standard ones.

John

SCOTI · 10-25-2002, 11:03 AM

I believe the RamJet cam spec's are .431/.451. You prob could run up to .470 lift max but the real question would be how long will the stock springs last w/more lift than the factory intended. The LT4 valvespring upgrade is good insurance & they have passed GM's 300 hr. full throttle test so they should last 100k in your motor.

10-24-2002, 10:47 PM	#1
chevjayfsd Project 7dos Join Date: Aug 2001 Location: Abilene, Texas Posts: 876	Vortec Head Question???!!!! Can anyone tell me what the biggest cam you can run in the vortec heads. I have a 350 w/vortec heads and my cam recently went flat and i am replacing it...Can someone do some research(I wouldn't know the 1st place to start looking). I have a .454 lift in it right now and i have heard you can go bigger... Thanks Jason __________________ 7DOS - 1972 C-10 350/350 Porterbuilt/Accuair 20x8.5/20x10 Ride Low or Die PSSST - Yes it's bagged. 7dos build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=610290

10-24-2002, 10:55 PM	#2
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	why do cams go flat? do the lifters hang up? __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

10-24-2002, 11:21 PM	#3
truckster Senior Member Join Date: Jan 2001 Location: Orem, Utah Posts: 7,954	The factory specs for the vortec say .5 inch lift max with the stock springs. __________________ I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson

10-24-2002, 11:23 PM	#4
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	this gets a little quirky...most publications say dont go over .460 lift...then ever one says the 350 ramjet has .480 lift with vortecs. Then I read never go over .450 ever(with out the spring upgrade). My suggestion...go with the spring upgrade to be safe. Jim __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

10-25-2002, 03:45 AM	#8
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	I'd say whatever cam they spec in the RamJet is probably as big as you can get. The 350HO 330hp engine uses one in the low .450's... FWIW, messing around with Desktop Dyno, the Comp Cams XE256H seemed to work really well. WIIIIDE torque curve, and lots of it. __________________ Project1970 - LS1 Swap Complete!

10-24-2002, 11:24 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Having never read any GM papers on them, I am going by what all the magazines say... .480 due to the lighter spring pressure.

10-24-2002, 11:25 PM	#6
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	I dont believe you can run that much lift with stock springs on the vortecs.......I think it was in the .460-.470 range.

10-25-2002, 12:08 AM	#7
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Scoggin-dickey has som info, If i can get the page up.... it sounds like to about .450 lift. http://www.sdpc2000.com/cart.asp?act...art&catid=2172

10-25-2002, 07:42 AM	#9
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	It's easy enough to check for coil bind when you assemble the engine. I have heard it is close to .500. __________________ Tim

10-25-2002, 10:23 AM	#11
chevyracing Registered User Join Date: Oct 2002 Location: Go to the middle of no-where then go another 25 miles East. Posts: 8	If you run more than a 465 lift you need to have the heads machined for clearance on the valve guides. It runs about 25 bucks a head to do this to. Scogin sells a set of heads that already have the machining done for an aditional charge, I am not sure but I think they run about 30 bucks more than the standard ones. John __________________ Life begins at 100 miles per hour, then just keeps getting better and better the more you mash the gas.....

10-25-2002, 11:03 AM	#12
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,031	I believe the RamJet cam spec's are .431/.451. You prob could run up to .470 lift max but the real question would be how long will the stock springs last w/more lift than the factory intended. The LT4 valvespring upgrade is good insurance & they have passed GM's 300 hr. full throttle test so they should last 100k in your motor. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*



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