I'm changing my cam and upgrading my valvesprings and since I already have bigger spring pockets and +.100 valves why shouldn't I run the bigger 26120 valve springs, seems like a win, win. In my mind, I'd get the better valve control, and reduced harmonics of the beehive spring, with more conventional spring pressure. Feel free to set me straight, Thanks.

 

Cam type and specs? Other valvetrain specs...

The 918s are MORE than adequate for most SBC builds. No need to run the bigger springs.

 

The heads I recently purchased have 918s on them, and they are good to at least .600" (what comp rates them at) lift, maybe even a bit more. Some even push it a bit with lifts up to .610". I think the 920s are rated to .630" or something. At the shop where I bought my heads they have TT Vipers with over 1000rwhp running 918s. I've yet to see a true "street" SBC running well over .600" lift in person so I'd take a guess that they will be enough.

 

I was pretty sure that the 26120's are rated at less lift than the 26918's, something like .580". Of course, that's with the recommended install height. They are also a BBC spring so you may need to machine the heads, but I'm not sure on that.

You need to check your install height with those valves first, and then you can choose a spring more accurately. Shimming may be required no matter what.

Also, give us your cam specs. (@.050" and @.006") That will help us.

 

The cam I'm going with is very similar to the GM 847 cam, I have a set of cc1.46OD springs on it right now installed @ 1.8 with about .080 worth of shims underneath. I figured take about .050 worth of shims out, use +.050 locks and I'd have a 1.9 installed height and serious overkill on the springs for slightly less cash outlay than 918's, retainers, and locators and locks. I know it's overkill, but will it hurt anything. I know I sound disrespectful of your opinions, but I'm not I really appreciate the input. This is just the debate I've been having with myself.

 

You don't sound disrespectful at all and I hope I don't as well. My opinions are just that. They are not nearly as educated as some others here with real world experience, I just know what I've read from reputable sources.

Do you know what spring pressures you have? (seat, nose and open) I'm guessing they're dual springs? An increased install height may be overkill for coil bind clearance, but cause less spring pressure which may lead to valve float. Also, I'm not sure about using shims and the +.050" locks together, maybe just take out all of the shims. Again, depends on the pressures.

With the RPM's you have to turn with that cam I'd think that you really would benefit from a beehive setup.

 

Actually the 26120's must be installed at 1.9 to have .600 clearance, that's why to use them in a small block you need +.100 valves. At 1.9 they have 25# more pressure than 26918's at 1.8 and open they're 367#'s vs. my dual spring @ 379 which by the way has 145# closed. Maybe I'm old school but it just seems silly putting such a little spring in such a big spring pocket. Mainly the only reason I'm considering the 26120's is because I can. My peabrain thinks it is way overkill, but is there any such thing as overkill in the valvetrain?

 

As long as the lifters, pushrods, rockers and such can take what the springs are dishing out AND it's appropriate for your setup, try it out.

 

I think I might, It looks like my block won't be out of the machine shop for a couple weeks, so I have time to think about it. Thanks again.

 

Sure! Too much spring can wreak havoc on lifters. And running a larger spring than necessary adds weight, which you don't want. That's the whole idea of the 918s: less weight with better valve control.