Matthew1821

Alright guys, so I have a stock L98 that i'm upgrading with a LT4 hotcam, I also got a pair of ls6 beehive springs and new come 787-16 retainers and fel pro valve seals for it all. But my question is, is it safe to run the LT4 hotcam wit 1.6rr in this current setup?

Tuned Performance

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Matthew1821

Yes those are the specs, however I read somewhere on the forum that i could run these springs can not have to machine anything.

Orr89RocZ

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Drew

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The stock cast iron heads have the intake and exhaust valve spring seats machined to different depths. There is no way to install the LS beehive springs to the proper installed height without having the shallower spring seats machined deeper. Tried offset locks, but didn't have enough valve stem to properly seat in the rockers. Further, you'll probably want to open up the pushrod slots for clearance with 1.6 rockers. With those machine shop operations, you might as well have the heads machined for screw in studs, guide plates, and more lift anyway... Which then begs the question, why put the money into machining the stock heads? Might as well go aftermarket. At least that's the conclusion I came to right before I put all the stock garbage back together and put the valve cover back on. LOL

Matthew1821

okay I'm getting mixed reviews on that, lots of people are saying you can run ls6 beehive springs with the stock heads and no machining and a few say you cant. The installed height for the beehive should be 1.85 in an iron l98 head and the springs height should be 1.73. Could that be enough or you think a couple shims could do the trick, I'm really trying to not bring it to the machine shop.

Matthew1821

This is what i'm referring to for the spring clearance

Matthew1821

whenever I put it in, ill measure from the retainer to the valve seal and let you know

Orr89RocZ

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Orr89RocZ

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Drew

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It'd work on Vortec heads because they don't have the dopey valve rotators. You can't use the rotators with beehive springs (and you wouldn't want to anyway). So you ditch the rotators and you have two different depth valve spring seats in the heads. If you shim the deeper seat, you'll miss the installed height of the blue GMPP LS springs. If you use an offset keeper on the shallow seat, your rockers will ride on the retainers instead of the valves and you'll chew up parts. I don't remember exactly how much room I figured I'd have for lift, since it was a moot point when the retainers hit the valve seals, because I couldn't get the installed height right without machine work.

I mean I didn't go through all the trouble of getting the parts, and tools, taking measurements, and so on, only to put it back together with the old parts, just because I wanted to... It really won't work on stock iron L98 heads, unless you want to pull the heads and have them machined.

Oh yeah, now I remember the lift problem of the equation... The stock valves have an extra groove for the O-ring that works with the old steel oil shields. You can dump the O-ring with positive type seals, BUT the groove is still in the valve. Around .480 lift (iirc) the O-ring groove will pass the lip of the positive type seal. So even with the valve spring seats cut to the right depth, the beehives will only buy you marginal room to increase lift, before the O-ring grooves will rip up the seals.

But hey, don't take my word for it, go ahead and spend a couple hundo and pull it apart and start measuring.