rocker arms...

[ericjon262]

conversion studs are readily available, and my understanding is the 3.1 MPFI guida will work on the 3x00, just not the 3500.

http://www.summitracing.com/parts/cca-4554-1/overview/

the other thing to take into account is the fulcrum diameter, it has to match the 3x00 rockers for the pedestals to work.

[onefastV6]

Have you had a chance to test mount a rocker on a cylinder head?
Aside from the pedestal difference, I believe the push rod length on the LZ motors may be different.

If this works it will be great, just need to take a lot of measurements first.

[ericjon262]

I haven't yet, to be honest, it's low on the priority list, pushrod length would probably change a little, might be able to get away with stockers, don't know. I'll try to do it tomorrow.

[ericjon262]

I went out and test fitted them, looks like a go, probably need new pushrods, when I installed one on the exhaust, there was a little play. I'll post pics tonight. FWIW, I'm going to try to pick a set up and run them.

[ericjon262]

installed a rocker on my LX9 3500, and it bolts on no problem with the LX9 pedestal swapped on. I didn't turn the engine over to see how the work through the lift curve, when I get the new engine back from the machine shop, I'll do a more thorough check.

a proper install will likely need new pushrods, and I would recommend valvesprings too as the 3x00 springs suck... On the exhaust valve I installed the rocker on, there was a very noticeable amount of play, over .060". this could work out to be a very cheap and easy mod for the 3x00 engines.

[caffeine]

Would be sweet if this works. Lighter valve train and extra lift what's not to like!

[ericjon262]

Would be sweet if this works. Lighter valve train and extra lift what's not to like!

I'll keep the thread updated, right now, I'm wondering is the pedestal will have clearance for the cam I have, may need to be ground down a bit, but that's no big deal. I need to find a clean set, or a new set though, the LZ4 I got this rocker off of, was trashed, poor car had parts thrown in every direction, including the dirt, which is of coarse, where all the rockers were...

[onefastV6]

Sounds like you need an adjustable pushrod to determine proper pushrod length. I would then turn the engine over by hand to check the rocker/ valvestem contact throught its full range of motion.

You shouldn't need to mess with the pedestal for a cam swap, just get the proper pushrods.

[ericjon262]

at max lift the rocker might possibly contact the pedestal, the LZ4 pedestal is machined for greater clearance where the contact might occur.

[3400-95-Modified]

I have a full set of rockers in route to me... so I'll be checking this on my engine too... Might be a bit nuts for my setup though but we'll see. I'll definitely have to check for piston/valve contact now since I had a tiny bit a few years ago with a badly stretched chain.

[ericjon262]

sweet! keep us posted!

Edit:

where did you get them, and how much did they cost?

[3400-95-Modified]

$30 shipped from ebay... LOL

http://www.ebay.com/itm/150991308580?item=150991308580&viewitem=&sspagename=ADME:L:OU:US:3160&vxp=mtr

going by application guides those should be the same as the ones you grabbed since the LZ4 is based on the 3.9L VVT

[ericjon262]

$30 shipped from ebay... LOL

http://www.ebay.com/itm/150991308580?item=150991308580&viewitem=&sspagename=ADME:L:OU:US:3160&vxp=mtr

going by application guides those should be the same as the ones you grabbed since the LZ4 is based on the 3.9L VVT

GM parts giant wants $18.79 each... you got a deal if they're clean and not full of dirt...

http://www.gmpartsgiant.com/Page_Product/PartDetail.aspx?Make=Pontiac&Model=G6&Year=2007&MakeCode=P&ModelCode=Z&CatalogCode=2Z1&SubModel=G6&eCode=LZ9&mCode=2ZM69&majorIndexID=00&SupplGroup=60&minorIndexID=GM00-491&SortKey=66

[3400-95-Modified]

Returns accepted and they said they are inspected to be quality used parts... so they better not be full of dirt... LOL if they are I can just clean them out too, that's not the end of the world.

[SappySE107]

Roughly .700 lift max on stock rocker. Roughly .540 max lift with 3900 rocker. Geometry on the valve tip at .540 is why we didn't move forward with making these work. Its already on that edge with very little lift. Interestingly enough, the 3400 rocker on a 3900 has the best geometry of all the combinations. Starts on the inside edge and is dead center for everything else.