Just thinking about the L92 heads, they flow 330cfm on the intake side and there cheap, so why don’t we see them on many trucks yet.

Sure the valves are huge 2.16/1.59, and the intake runners are huge something like 260 cc, but gm built these heads for 6.2L and 6.0L truck engines. These engines are VVT, and I think thats how they get away with the huge ports.

L92 heads + L92 truck manifold can be had for around $1000 total. I would have to make a cable tb fit it, and injectors and fuel rails.

The use of variable duration Rhoads lifters would allow a larger camshaft to be used and still retain low end power need to move a truck.
Rhoads lifters, shorten the duration at lower rpm, around 8-10 degrees, and mostly on the closing side. This is in affect advancing the cam timing, increasing dynamic compression at low rpms. Kind of like what the VVT on the L92 and L76 engines are doing.

Cam - something like 220-224 Intake/ 228-230 exhaust with a 114 LSA
I don’t think large intake durations are needed as much, because the heads flow so well on the intake side, but not so much on the exhaust.

Also try to get the compression up to 10:1- 10.5:1 by milling the heads. but piston to valve clearance?

What do you think, could this setup break the 400 rwhp mark? And still be torquey for daily driving?

 

L92 heads are designed to work with 4.00" and up bore sizes,you'll need a different intake manifold sounds like a great combo to me.

 

They are relatively new and not a whole lot of people have 6.0s right now much less the extra coin to throw at the L92 setups. Hell the first L92 setups are jsut getting on the road over on tech. Give it some time and the L92 setup will be on everything except the highest of boost/nitrous apps, IMO. I have a set on order from WCCH but it will be 2+ months before I get them and its for my 418 not an LQ4.

 

I have also been researching this option and wonder how a LQ4 would respond to the L92 top end. I was told the L92 heads really need the stroke of a 408 but I don't see why they wouldn't perform well on a LQ4 with the right cam.

 

They dont need the stroke of a 408 they need the bore, a 4" bore is cutting it close and will cause some valve shrouding. They are made for a 4.050 bore so that is part of the reason for the LARGE valves. Im sure they woudl perform very well on an LQ4 with the right setup of compression and valve events.

 

I know a lot of the L92 is uncharted territory. You need at least a 4.000 bore to run these heads and yes valve shrouding could be a problem. The best bet would be to bore the block .030 over and run forged rods and pistons. The stroke of a 408 would be a nice addition this setup, but may not be needed.

 

Oh if you can swing the stroker crank then most definately do, cant go wrong with displacement in most cases.

 

A 4.00" bore may shroud the valves, but the way I see it is, GM put these heads on the L76 and it is a 6.0L.

 

Is the L76 a 4" bore? Im only familiar with the 6.2L with the 4.05 bore.

 

As long as the valves fit, I would run them. I wonder if there is a point at which a smaller valve would flow more than a larger valve in the same size bore?