Jim85IROC

iTrader: (6)

I'm building a stroker 6.0 and plan to use LS3/L92 heads. I had planned on LS3 heads so that I will have the lighter weight intake valve, which will let me use a little lighter valve spring. I got to thinking and wondered if the hollow valve will be sufficient for a n/a 500RWHP motor that I plan to hit with a 200 shot from time to time.

Am I better off with the heavier L92 valve, or do I even need to take it farther and go with aftermarket stainless valves?

Robin L

First you don't want a "lighter" valve spring. You want as much spring as the stock spring pad will allow in my opinion.
The LS3 hollow stem valve will be fine. If you want to spend some extra then step up to the titanium LS9 intake valve.

500 RWHP is attainable with some comprimises. The 200 shot is also getting close if you intend to use a plate through the stock intake. The front cylinders will have some issues with that setup if you don't get everything perfect.

You could have a VERY reliable 480 ish RWHP and have no problems with a 175 through the stock intake.

Robin

Jim85IROC

iTrader: (6)

Why do I want as much spring pressure as the spring pad will allow? I always thought that you don't want to over-do it with spring pressure because you're needlessly taxing your rockers, pushrods & lifters?

Ultimately though, the reason I ask is that I initially wanted LS3 heads, but getting them used is quite a bit more difficult than finding L92 heads, and if I'm not going to benefit from that lighter valve, then I might as well save myself the money and just buy L92s.

As for my power levels, I won't be broken-hearted if I wind up with slightly less HP. My goal really is to have a big wide torque curve with good drivability. For the nitrous, it's unlikely that I'd ever go past a 150 shot, but I just like to have that safety margin in my parts so that I don't have to worry about destroying something.

Robin L

I said as much spring as the stock spring pad will allow. That will be your limiting factor.

It's a old myth that you want "light" valvetrain components. It's better to have too much mass and spring pressure than not enough.

More later, gotta run.

Robin

Jim85IROC

iTrader: (6)

Thanks for the help. A lot of this is new to me, because the last motor I built was a 350 SBC about 10 years ago, and it's a very mild motor, so none of this was ever an issue.

1lejohn

iTrader: (9)

REV also makes a nice lite weight replacement valve for these heads. The TI valves are $$$. I sprayed many 150-175 shots on the GM LS6 valves. The LS3 's with a good spring should work.