Installed height? Guide plates?

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I’m getting ready to get on with dropping a cam in my Vortec 350, does anyone know what the stock installed spring height is? I’ve heard it’s 1.7 and 1.75, the springs I’m using are .560 lift at 1.8 installed height so I’m gonna be losing .050 lift out of the spring. I’ve taken in consideration the option of running .050 offset keepers. But I’ve heard that doesn’t leave enough valve tip for self aligning rockers, which would then lead me to running guide plates and needing to get the heads machinedfor those. The cam I’m running tops out at .495 lift and I know the recommended clearance is .050 seal to retainer, I could run .030 offset keepers but that would limit my spring lift to .540. Anybody do anything similar on vortec heads? Anything helps including part #’s causing I’m looking for a good set of seals that would increase my clearance aswell.
 

Erik the Awful

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What are you referring to as "spring lift"?

Is this your only vehicle, or can you have the heads off and sitting on the bench while you mock up the parts and take measurements?
 
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What are you referring to as "spring lift"?

Is this your only vehicle, or can you have the heads off and sitting on the bench while you mock up the parts and take measurements?
I can have the heads on the bench mocking everything up for some time, just trying to map it out before I begin tearing into it. By spring lift im talking about the lift the spring can handle at its installed height.
 

Erik the Awful

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Here's the specs for Melling's replacement spring:

Closed spring height of 1.700" and coil bind at 1.200". That gives you a hard upper limit of .500", but you don't want to get too close to that. The specs list an open height of 1.270, which is on the high end of clearance, according to this article from Hot Rod, .060" is the old spec - and probably pretty close to what the factory setup on these engines can handle. That would give you a max valve lift of .440" on stock springs. I live dangerously, so I'd probably go up to .450" without worrying too much.
 

Schurkey

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Vortec 350

does anyone know what the stock installed spring height is? I’ve heard it’s 1.7 and 1.75,
Should be in the factory service manual. Download the service manual set for your vehicle from the links in the Sticky section of the Engine forum on this web-site.

Or pull some springs off your heads, put the retainer and keepers back on the valve, and measure it yourself in several locations--intake and exhaust. Installed height can vary with valve and seat recession, which is why they make valve spring shims.

the springs I’m using are .560 lift at 1.8 installed height so I’m gonna be losing .050 lift out of the spring.
0.100 if the actual installed height is 1.700 instead of 1.750.

I’ve taken in consideration the option of running .050 offset keepers. But I’ve heard that doesn’t leave enough valve tip for self aligning rockers, which would then lead me to running guide plates and needing to get the heads machinedfor those.
You'd certainly want to verify that the self-aligning rockers had clearance to the keepers/retainers.

Probably easier to have the valve pockets cut down if there's enough material to do that, or just buy longer-stem valves. The OEM valve are nothin' special; you could solve your installed-height issue AND upgrade to one-piece valves at the same time. MIGHT need longer pushrods, though.

The cam I’m running tops out at .495 lift and I know the recommended clearance is .050 seal to retainer, I could run .030 offset keepers but that would limit my spring lift to .540. Anybody do anything similar on vortec heads? Anything helps including part #’s causing I’m looking for a good set of seals that would increase my clearance aswell.
Machine the valve guides a little lower, if the additional installed height doesn't give you enough clearance to the seal. 1.800 - .495 valve lift = 1.305. 1.305 - .050 clearance to the seal is still 1.255. You said your springs are good to 1.800 - .560 =1.240.

I'd look for new valves and probably new pushrods to match.

Or get a cam with less lift.
 
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