[waid786]

I have seen many posts all over the internet of people saying the LS6 valve springs will fit the 96-00 Vortec 5.7 heads using 787-16 Comp retainers and stock Vortec keepers, thus requiring no machine work. Numerous threads say they will fit or show a head on a bench with the springs installed, yet I have not actually found where anyone is driving a car with this combo installed. If the Comp Cam #26918 is a replacement it would reason that the LS6 spring would work.

It seems that most of the magazine articles that I came across to increase valve lift points to Comp Cam #26918 springs (due to advertisement money?) rather than significantly cheaper LS6 springs. None of these article mentioned LS6 springs. The LS6 spring is $68 and the Comp is $193.

The maximum RPM in the Corvette Z06 is 6500 rpm. My 350 with Vortec heads w/LS6 spring will rarely see 6000 rpm if ever. I am thinking if the GM OEM springs are good enough for LS Roller motors, then they should be good enough for 400hp vortec build.

I am going to replace my original 77 350 top end and replicate GMPP 350HO:

-GMPP Stock Vortec Heads (#12558060)
-GMPP Cam (#24502476)
-Edelbrock Performer Vortec Intake (keep my q-jet). I really want the air gap but that means new carb.
-Fel-Pro 0.015” shim head gasket to bring up compression to around 9.1-9.5 :1
-Long tube headers

I was thinking about the comp cam XE262 or even the XE268 with 1.6:1 rockers which would put the valves beyond the vortect limit of .481. This is why I was thinking about the LS6 springs for low price of $67.

With the GMPP #24502476 cam, the exhaust valve lift with 1.5:1 factory rocker arm ratio 0.460. The Ramjet 350 has stock vortec heads, roller cam, 1.6:1 rockers which puts the max valve lift to .481".

http://www.gmperformanceparts.com/_r...Jet_Engine.pdf

Anyone here actually using the LS6 spring and using it?

Waid

[1996thunderchicken]

edelbrock has a performer air gap that allows the use of q-jets and its a spread bore just like the performer intake

[F-BIRD'88]

Why don't you just buy the GMPP Bowtie Vortec heads and bolt them on and go.
They make more power than stock vortecs and are all set up for high perf.

[cobalt327]

Originally Posted by waid786

I have seen many posts all over the internet of people saying the LS6 valve springs will fit the 96-00 Vortec 5.7 heads using 787-16 Comp retainers and stock Vortec keepers, thus requiring no machine work. Numerous threads say they will fit or show a head on a bench with the springs installed, yet I have not actually found where anyone is driving a car with this combo installed. If the Comp Cam #26918 is a replacement it would reason that the LS6 spring would work.

It seems that most of the magazine articles that I came across to increase valve lift points to Comp Cam #26918 springs (due to advertisement money?) rather than significantly cheaper LS6 springs. None of these article mentioned LS6 springs. The LS6 spring is $68 and the Comp is $193.

The maximum RPM in the Corvette Z06 is 6500 rpm. My 350 with Vortec heads w/LS6 spring will rarely see 6000 rpm if ever. I am thinking if the GM OEM springs are good enough for LS Roller motors, then they should be good enough for 400hp vortec build.

I am going to replace my original 77 350 top end and replicate GMPP 350HO:

-GMPP Stock Vortec Heads (#12558060)
-GMPP Cam (#24502476)
-Edelbrock Performer Vortec Intake (keep my q-jet). I really want the air gap but that means new carb.
-Fel-Pro 0.015” shim head gasket to bring up compression to around 9.1-9.5 :1
-Long tube headers

I was thinking about the comp cam XE262 or even the XE268 with 1.6:1 rockers which would put the valves beyond the vortect limit of .481. This is why I was thinking about the LS6 springs for low price of $67.

With the GMPP #24502476 cam, the exhaust valve lift with 1.5:1 factory rocker arm ratio 0.460. The Ramjet 350 has stock vortec heads, roller cam, 1.6:1 rockers which puts the max valve lift to .481".

http://www.gmperformanceparts.com/_r...Jet_Engine.pdf

Anyone here actually using the LS6 spring and using it?

Waid

Member 'spinn' is one who comes to mind that is actually driving around w/them. Here's one thread, he's posted in other threads- Other tthan Vortec heads

There are many ways to go about this, as you may already know. From Comp springs and retainers to ghetto grinding the original retainers, to buying a $50 tool to rework the guide bosses yourself, etc.

[Custom10]

Originally Posted by 1996thunderchicken

edelbrock has a performer air gap that allows the use of q-jets and its a spread bore just like the performer intake

The air gap is a high rise RPM manifold, there are no eddy air gaps for the Qjet spread bore and vortec heads that I know of? They do make a performer non air gap though for a qjet/vortec application.

[techinspector1]

Originally Posted by waid786

I was thinking about the comp cam XE262 or even the XE268 with 1.6:1 rockers which would put the valves beyond the vortect limit of .481. This is why I was thinking about the LS6 springs for low price of $67.

With the GMPP #24502476 cam, the exhaust valve lift with 1.5:1 factory rocker arm ratio 0.460. The Ramjet 350 has stock vortec heads, roller cam, 1.6:1 rockers which puts the max valve lift to .481".

Not sure where you came up with the 0.481" Vortec limit. The 062 and 906 heads, as produced by Chevrolet, are limited to about 0.420" lift at the valve. The total clearance from retainer to seal is about 0.450", which leaves only 0.030" clearance at 0.420" valve lift. Any further lift without adding more clearance can result in wreckage.

Further, I would not use an extreme energy grind, period. If you want to raise the static compression ratio and put more cam in the motor on 1.5 rockers, great, but I wouldn't ask the valvetrain to endure 1.6 rockers with an extreme grind of cam.

[waid786]

Correction. It is 0.486" !!!

[waid786]

Here is the retainer.

[lmsport]

Cut the guide boss and run the LS beehive spring and CC retainer. There are some lighter retainers out there but not necessary for your application.
I have run those springs alot in oval racing crate engines without any durability issues turning 6800-7000.

[retorq]

New guy here .... I run them on my Vortec swapped 95 TBI Tahoe. Did yellow LS6 springs, Comp 787-16 retainers, used the old keepers and I used 1986 Dodge Daytona Turbo engine valve seals. This engine has sees 5500 and never misses a beat.

[DENCOUCH]

Originally Posted by waid786

Correction. It is 0.486" !!!

Now subtract the thickness of the retainer, ya don't want to leave that step out.

[waid786]

retorq, what is the part number of the 1986 Dodge Daytona Turbo engine valve seals?

How much does it adds to over all increase in the lift?

Thanks

[techinspector1]

Originally Posted by waid786

Correction. It is 0.486" !!!

I think you'll find that most any cam grinder out there will recommend leaving a safety margin. Here's the verbage from Lunati....

"Valve Spring Retainer to Valve Seal Clearance
The distance between the innermost step on the valve spring retainer and the valve guide must be 0.090" larger than the maximum valve lift of the camshaft. Measure the distance between the top of the valve seal to the bottom of the valve spring retainer. After adding 0.090" to your measurement, it should still be larger than the maximum valve lift of the camshaft. If not, machining of the valve guide in necessary for adequate clearance."