LT4 LT4 Valve springs

[BlackNBlue95]

I have a set of lt4 heads I am looking to install along with an lt4 intake.. I may possibly be using a comp cams, extreeme energy 306 cam and I needed to know what kind of valve springs I should use and hopefully without having to machine the heads. I have heard the stock valve springs on the lt4 will not hold up to the cam being it has .510/.540 lift and I am using the lt4 1.6 ratio rockers... Any suggestions on valve springs/retainers would be appreciated.
-Rick

 

[BlackNBlue95]

For stock LT-4/ZZ4 I show:

GM PN 12551483 Single Spring O.D. 1.32", 101# @ 1.78" installed Height, with 332 average rate of #'s/in. Retainer PN 10212808.

The Hi Performance GM is:

PN 330585 HD, recommended for competition camshafts with .560" maximum valve lift. It is a dual valve spring, O.D. 1.379", 140# @ at 1.75" installed height of 1.75", with 440 ave. rate #'s/in.

Umbrella-type valve stem seals are recommended. Use with aluminum valve spring retainer P/N 330586.

C'ya
D

Wait those springs you reccomemded are a GM part number? and also will they work without head machineing I really want to get away with installing the springs my self and not having machine work done until I port them in a few years...
-Rick

 

[BlackNBlue95]

BTW my lift will be more like .533/.576 with the 1.6 rockers I am told..

 

[sothpaw]

Get the springs from Comp cams if it is a comp cam you are buying.

I have comp cam 941 spring, no mod to the head was needed. But the spring force is very high. I have .566/563 lift, more than you.

 

[BlackNBlue95]

I decided I am sending the cam back and I will be getting something different.. along with the manufacturer reccomended springs ect..

-Rick

 

[FX GS]

I have to ask, so please excuse me, but if your are an ASE Master
Certified Technician, work at a Chevy dealer & adverstising that you should be contacted for doing high performance work, why are you asking these questions?
If I'm missing something, I apologize.

P.S. My condolances on the Cubbies.

 

[BlackNBlue95]

I have to ask, so please excuse me, but if your are an ASE Master
Certified Technician, work at a Chevy dealer & adverstising that you should be contacted for doing high performance work, why are you asking these questions?
If I'm missing something, I apologize.

P.S. My condolances on the Cubbies.

LoL.. You're not missing anything, I don't know everything, noone does. I ask questions so that I can get it right the first time. BTW ASE Certifications only apply to general service and repair, not performance.

-Rick