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Vortec Valve Springs

27K views 33 replies 8 participants last post by  Ken K 
#1 ·
Can anyone tell me if Elgin RV 943X valve springs will drop into Vortec heads without any machine work. The springs are suppose to be good for .490 lift and the cam I am using is .454 lift.
 
#7 ·
Ken K,

I am using Vortec heads on my build with a Comp cam. I had the heads assembled by my machine guy. He used the comp springs and used the old retainers. He said that the old retainers are harder than than the Comp retainers. He also told me that I did not need machining of the heads as long as the lift stayed under the .500 mark.

He did say once you hit the .500 mark, I would need machining. He also stated that if I went to a bigger spring and bigger mod (cam lift) I would need to machine since the stock Vortec heads had pressed studs. Meaning they would need to machine threaded studs and bring down the valve guides.

So, if I understand him correctly, you should be fine with your set-up.

Mike
 
#8 ·
I bought the cam with the .454 lift just in case. I think the Z28 springs are better than the stock Vortec springs. I was told by someone the Z28 springs would drop right in. I will try and use the stock Vortec retainers. I have not got that far yet.
 
#12 ·
Ok, so I used the search function and this appears to be the right thread for my Vortec valve spring questions.

Engine is a 350 with brand new (stock) Vortec heads and I'll be using a ZZ4 cam (208/221 @ .050", .474/.510 with 1.5 ratio). I'd like to use 1.6 ratio rockers if possible, taking lift to 506/544, unless someone can point out a good reason not to.

1) Bill mentioned the Comp 981 springs, and that they worked without any machining. He also said he used the Comp retainers and locks. Can anyone comment if these will still drop-in using the stock retainers/locks. Maybe I need to ghetto grind the stock retainers along with the spring change?

2) As this isn't going to be some high-strung race motor, can I just do this spring swap in my garage? Do I need to worry about installed-height? I've disassembled heads before, I know it's not difficult. But that was probably 15 years ago. This seems simple enough that I shouldn't need to involve a machine shop. I will take them in if I have to, but trying to keep this a budget build.

I got great deals on both the heads ($300/pr, brand new in the box) and the cam ($50, brand-new takeout), so I'm just looking at my options for making them work together.

This is going into an otherwise stock '63 Vette / 4sp (wide ratio) / 3.36 that is for cruising and might only see the strip just once to see what it's capable of. Mid-high 13s or trapping over 100 would be plenty fast for this car. I think this setup should do it.

Thanks,

-Dave
 
#13 ·
I have a set of springs from some AFR heads. I took them into a machine shop and asked them about installing them on the Vortecs. They told me it was not a good idea. I had the springs tested, they said they were 120 lbs. I was told the springs will lose 10 lbs as soon as the engine is started. The Z28 springs are rated at 110 lbs.
 
#16 ·
I think you'll be crashing the retainer into the guide boss unless you machine the heads. That is a lot of lift for un-modified Vortecs. You'll almost certainly need to machine above .480" lift, and I don't think those Z28 springs are good for much more than .500".

With the lift you'll be running, I'd be looking at Comp Beehives and a "drop-in" solution.

Also, you did not say it, but I assume you have a 87-up roller block? You'll need a newer block to use the factory ZZ4 cam.
 
#19 ·
=
On most Vortec heads the bottom part of the guide boss is too big in diameter for the 943 "Z28" spring
I have seen were some have said they went right on but that has not been my experience with any Vortec head I have dealt with
If you remove the damper you defeat half the purpose of using the 943 spring
 
#20 ·
How much work is involved in machining the guide boss so the Z28 springs work? I'm in too deep now, I need to make them work. I have to use a 2 piece rear main seal block because of the small flywheel otherwise I would have used a roller cam block.
 
#21 ·
First you need to see if they drop on, might get "lucky"
But it is not a big deal to have them machined you just need the guide boss cut down to clear
You can do it yourself if you want to buy the cutter
Comp sells one, actually two
One for the guideboss & seat & one for the top part of the guide if it needs shortening which in your case it should not at .454
Have never seen a set that would not clear at .460 or so & many that would clear at about .480 but it does need to be checked
Just put the valve in with seal installed & the retainer & locks on & see how much room you have between the bottom of the retainer & the top of the seal

All real simple stuff for any competent machine shop ;)
 
#22 ·
The heads came from a machine shop. I thought I could just use the AFR springs since I already had them. They mentioned something about machining for $50. If I have to have machine work done, am I better off using the springs from the AFR heads? I have the retainers that go with them.
 
#23 ·
How about trying the springs on the heads to see if they clear,,,,
And testing to see you have enough retainer clearance
Then you will know,
No one can tell you for sure without looking.. that is what mocking up for assembly is all about ;)
 
#25 ·
I'm not using a ZZ4 cam in a early block. I am using a flat tappet Crane cam. I have a roller cam block but I can't use it in a 79 El Camino with a 4 speed. It uses a special bellhousing and I have to use the small flywheel. The factory roller cam blocks all use the big flywheel.
 
#27 ·
Strange...casting variances, I'd guess.
I've used -906 heads if that makes any difference.

I've built two Vortec headed small blocks in the past. One project engine still resides in the '69 Malibu in my garage.
The Comp -981 springs worked on all 4 heads without having to machine the OD of the guide boss. I did machine the tops for guide/retainer clearance due to cam lift on one pair. The other set was fine as is for a Voodoo 60101 cam.

But, as Mike noted...machining the ODs is a simple fix.
 
#32 ·
Ken
This is really pretty simple
You cannot fit square pegs in a round hole unless you use a really big hammer,,, :D

The damper MUST CLEAR THE GUIDE BOSS
There is no top & bottom to the "Z28" spring, the damper & spring will be the same length once compressed & installed
The "AFR" spring is 1.430 or so right?
It is not going to sit in the spring pocket of a Vortec head unless you machine it
It will not fit any stock GM casting except for the Bowtie stuff
A 981 Comp will just fit on some Vortec castings, but the 943X generic $30 Z28 spring is not a Comp 981
From memory the 943 is ±.870 ID so,,,,,,,
It is not going to fit a head with an .870 to .900 guide boss very well if at all unless you happen to have s set of heads with the bottom part of the guide on the small side

If the damper slips over the bottom part of the guide boss it will work
If not it will not without machining
 
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