Valve spring upgrade on 810 heads?

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I'm rebuilding a roller block 350, its been bored .030 over.
I currently have the roller cam and all its supporting assembly from a low mileage vortec.
Plan is to mildly port and polish the heads and put either the stock vortec cam or a mild roller cam into it (Rock Auto has the 93-95 LT1 cam for $360 shipped).
This is not a fancy build, just low revving, reliable, tbi torque.


The TBI heads are the heavy duty, oddball 810's,
they have rotators and oil shields on both valves, the exhaust valve stem is a 3/8 thick stem- and sodium filled. spring seats are both cut deeper in the heads.

The question is about the valve springs.

The stock 810 valve springs are the same duel springs in the 193 heads, just set lower into the head to make up for the height of the shield and rotator.

I'm looking for ideas or opinions on valve springs for the roller cam.
Would the common Z28 springs be suitable?
I'm not sure about removing the shields and rotators, I don't think shimming the spring that high is a good idea.
Is using the "z28 springs" with the shields and rotators a problem (added valvetrain weight/ possible extra things to break)?

I have the stock Vortec springs, i know the spring rates are claimed to be the same as the 810/193's but vortecs are a single spring. the vortec and stock 810 spring both have the same free height measurement.

Any input would be helpful..... I could also just pick up a set normal 193 heads instead and not deal with the duel rotators and deeper seats?

Thanks
 

Hipster

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Best bet is to get the springs recommended for that cam. You need to measure what you have. Springs that are under rotators are usually shorter as opposed to the spring seats being cut deeper. Getting the seats cut sinks the valve into the head and so does facing the valve so your into shimming anyway. You really didn't say how far you're going with the heads. Crane Cams used to have the most comprehensive online catalog the list spring pressures at different heights for a given spring. Also need to check for coil bind and retainer to guide/seal clearance with the new stuff.

Check this place out.
 
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the heads are cut down from the factory,
the springs are the same, factory springs used in the 193/191 heads.
The 810/193/191 springs are the stock spring height, they also measure the same height as the stock vortec spring.
the seal to retainer height is between .449 and .457- which should be fine for the factory LT1 cam.

GM ressesed the factory spring pockets to allow the use of the rotator and shield, with a regular height valve and regular spring.

the springs for a factory LT1 cam are the same spring height/diameter as the 193/810/187 springs... but they do not use the rotators or shields.

the LT1 springs do have slightly higher seat and open pressures...... hense trying to use the "z28" springs that are commonly swapped into these and many other sbc heads.
but again most people don't use the shields and rotators...... so are they just shimming the spring up an additional .105' to get the correct height?

OR is it more preferable to use the old factory shields and rotators with new springs and not have to shim the spring up so high?
 

Schurkey

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Are the rotators on top of the spring, or under the spring?

Oldsmobile was stupid enough to put the rotator above the spring, so all that weight could jump up and down a zillion times an hour.

Chevy big-blocks had the rotators under the spring--no moving mass to deal with.

When I scrapped the rotators on the L29 heads that went on my boat, I used two sets of rotator eliminator shims. They made two part numbers for those shims--with and without beehive springs.

I suppose they make something similar for small-blocks. Haven't looked.
 
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