Valve spring upgrade on 810 heads?

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

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.

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.

I'm doing the same thing, and as the original poster stated, valve pockets are deeper in the 810 heads to cater for the rotators when using GM "standard" lenght springs. (rotators that sit on top of the valves, adding weight unfortunately).

Infact the 810 casting is altered so the pockets are not really cut deeper, the casting on the 810 is lower in this area and the spring pocket cut is about the same as for the inlet valves on a 193 head. Anyways, the ideal situation would be if a guy could use springs with 0.1" taller installed height and no shims when the rotators are removed.

I did a quick check on one exh.valve on the 810's and installed height for the stock springs appear to be just under 1.72 (1.7185) If I measure with a stock 193 inlet spring retainer instead if a rotator the installed height is 1.8310. (Now the 193 retainer will obviously not work with beehives, but gives an idea of where an aftermarket non offset setup will end up.) The above measurements does not include the spring "shields".

This means an LS type beehive spring with suitable spring rate for the cam in question could be an excellent choice as they are typically installed at 1.8" Especially as the smaller retainer and lighter valve would offset most if not all of the extra 10grams from the thick stem exhaust valves.

I've seen the beehives mentioned in several cam threads here. Anyone care to share their findings? Like what retainers an keepers to use.
Most likely when used with "regular" height valve pockets some kind of offset hardware would have to be used, right?

The Cam I'm planning to go with is either:

#1 Lunati 20080678
I have a soft spot for "UDharolds", Harold Brookshire's work. He truly seemed to be in a class of his own, but passed away 2015.

Recommended here in 2008 by Harold himself for a different but not too different application. (Carburated Vortec block with double humps, 9.1-9.4CR and a request for "NO lumpy idle )

#2 Comp 08-500-8, an XE gind thats seems to be recommeded over the 08-300-8 for use on TBI engines.

#3 Comp 08-300-8 probably less agressive ramps and definitely less exhaust duration, a little bit closer to a single pattern cam than the others. Seem to be recommended primarily for TPI engines for some reason? Used to be on top of my list before I realized that.

I put stock LS2 beehives on my Vortec heads with Comp Cams 787-16 retainers and new stock keepers. By the numbers they're about 10% stiffer than the stock springs. I'm running a bit more aggressive cam than those you posted.

Erik the Awful said:

I put stock LS2 beehives on my Vortec heads with Comp Cams 787-16 retainers and new stock keepers. By the numbers they're about 10% stiffer than the stock springs. I'm running a bit more aggressive cam than those you posted.

Click to expand...

Great info, thanks!

Looks like those retainers will work. I might possibly need a set of 0.050 or even 0.075 "Down locks" to put me right in the ballpark, as one of the Reviews state the installed ended up at 1.75...


How much do you rew that thing?

The transmission's junk, and so was the previous one, so not much yet. The heads' flow is the biggest limitation, so it probably won't see much over 5500 rpm.