Hello!!!

I'm putting a L31 5.7 engine on my bird and I have some questions about the cam setup:

I gonna use a LT4 Hot Cam (with stock vortec heads ) so a searched on the web some info and I found that I have to change the springs and the retainers of the heads, the question is:

I only have to change the springs and retainers?

Do you recommend change the roller lifters?

My budget for the heads and cam is like $550.

My setup is:

Engine: L31 SBC 350.

Heads: Vortec 906.

Transmission: 700r4.

Carburetor: Holley 750cfm Sec. Vacuum.

Intake: ????? (You can recommend a good option)

end gears: 3.42

Thanks!!

 

search. several threads already on this. Tons actually.

Factor rollers are fine if they are good now.

Edelbrock Performer RPM.

For me, with 1.5 rockers, I only had to change the springs and retainers. ( I also changed the seals, but that could be debated) However, I could not go with the 1.6 rockers in the kit due to retainer/guide clearence.

Alex spring kit is popular, but Ive read people that hate it, so do your research.

 

Thanks for reply.

I know there are many threads about this, and I searched but always is good be sure
and get the opinion of people that have a good experience.

The stock heads come with a 1.5 rockers? Sorry for my ignorance

 

Yes. stock is 1.5

 

To get the lift of the Hot cam you need 1.6 rockers.
There are other roller cams available that give the same or better lift with 1.5 rockers

Unless you are going to spend all your time at the track you might consider a smaller carb.

Ditto the intake choice , there are some good dual plane intakes that give both economy and perf ( depending how you drive ? )

 

Thanks for the reply

Quote:
Originally Posted by Jose Zuñiga View Post
I gonna use a LT4 Hot Cam :
To get the lift of the Hot cam you need 1.6 rockers.
There are other roller cams available that give the same or better lift with 1.5 rockers

Quote:
Originally Posted by Jose Zuñiga View Post
Carburetor: Holley 750cfm Sec. Vacuum.
Intake: ????? (You can recommend a good option)
Unless you are going to spend all your time at the track you might consider a smaller carb.

Ditto the intake choice , there are some good dual plane intakes that give both economy and perf ( depending how you drive ? )

Thanks for the reply.

What cam do you recommend? Some people say that the LT4 Hot cam works very well with a vortec heads.

About the carb, I'm gonna buy a smaller carb. In the future I'm going to stroke the engine and do other mods so the carb has to be prepare to support it.

Do you think that this springs, retainers and roller rockers will work great on the vortec heads?

Howard's cams valvesprings good to .570 lift 1.26" diameter
Howard's spring retainers 7* lightweight tool steel 1.26" diameter
link: https://www.thirdgen.org/forums/engi...ml#post5669069

Roller rocker 1.6r:

http://www.ebay.com/itm/SBC-Chevy-Steel-Roller-Tip-Rocker-Arms-Self-Aligning-1-60-7-16-Vortec-305-350-/380543685132?pt=Motors_Car_Truck_Parts_Accessories&hash=item589a2bd20c&vxp=mtr

Really thanks for the help. Is wonderful see how the community help the members.

 

The springs are fine but you need your heads machined to use them

These springs and special retainers drop right in with no machining needed

http://www.alexsparts.com/valve-spri...rf-hyd-roller/

 

Awesome, thanks!! I'm going to buy it.

And what do you think about the roller rocker?

 

cheap junk. I bought a set years ago. Had to toss the nuts away, they were worthless. You are better off to save your money and get a quality set.

 

http://www.summitracing.com/int/part...make/chevrolet
http://www.summitracing.com/int/part...make/chevrolet

 

3rdgenmaro and vetteoz thanks for the help.

Now I know what I have to buy.

 

This is what I decided to go with.

http://www.summitracing.com/parts/sc...make/chevrolet

 

Guys thanks for the reply!

I bought the Alex's parts springs kit.

And I'll buy the Comp cam Magnum RR.

The question is that I researched like for 3 days what cam is beter than the LT4 Hot cam, the problem is that some people say that the XE274 is better, others say the CC305 is better so right now I don't know what cam I have to use.

Please give me a recommendation about that.

 

In my opinion, having run the Comp Magnums, the Comp Ultra Pro roller rockers are well worth the extra money.

 

Thanks for reply.
Is a lot different (about performance or quality)??

Because is a little bit expensive (This month I have to buy the intake, long headers, flat top pistons, MSD distributor, so I can't spend more money unless that part is necessary )

 

I am going to install a LT4 HotCam with L31 Vortec heads and 1.6 rockers (.525" lift)
The heads have the valve boss height machined down .200" for keeper to seal clearance.

Question is, what valve springs to go with for a budget build?
I have the tools to machine the valve seat pockets to 1.320, 1.430, etc
I have the tools to machine the valve guide to small ID for the 1.320, 1.430, etc

Cheapest would be to buy some Elgin RV943 springs (1.260 stock dimensions) and call it good.
But is the open seat pressure good enough for 6200 RPMs?
Or just get it over with and install the 1.430 springs? If so, who makes a budget kit?

 

LS6 springs have been working good on mine (1.5 rockers)

 

What is the installed height and closed seat pressure? What cam lift and duration? Roller?
I looked at them but not sure if my 220/220 duration roller cam would like the lower seat pressure with boost.

The lower seat pressure of the RV943 kind of steers me away from them.
The Alex kit lists a decent installed height and 135# closed which is good.

 

From summit: Beehive, 90 lbs. @ 1.8 in., 295 lbs @ 1.250 in., .570 in. Maximum Lift,

Not sure about your application, but many others have used them with success on the basic hotcam install.

But, I wouldnt start mixing the terms budget and boost. Atleast to an extent. Valvetrain especially. Get you a good set that fits exactly what you need.

 

Full roller parts. Reduced friction, better valve control.

A lot different? Yes.

Necessary? No.

Would I wait until I could afford them? Yes.
As long as the season didn't start first...