I see LSA's all over the place for the Gen3's. The SBE cams seem to use a wider LSA for P to V clearance. What do these engines like? I know the more efficient the heads are the less they need to rely on a tight LSA and the pulling of the exhaust on overlap for cylinder filling. In two of your examples,, one uses a 110 LSA, while another uses 117, with similar hp outputs

I have the same questions about the gen3 as the op.

I'm a bracket racer racing small blocks for a long time 30 plus years.My son and I both run two bracket style points programs at our local track.I have the same questions.
I'm only interested in na builds.

Why doesn't anyone make higher lift cams with a head that flows this much?Are the valves too short to get higher lifts?

I would think with the head flow these engines should make more na power.

With oem lifter .650 is the highest you can go on lift.
ric3xrt did a good & informative video on rocker motion.
Jesel makes nice lifters and rockers for an all out n/a build.

Rockers get funky when you approach .650" of lift. As said, you can get higher capability rockers but it's pricey

Wow I get back from vacation and see a bunch of amazing replies to this!

I plan to be running methanol fuel, some people had asked that. I plan to run higher compression like 11 or 12:1. Nothing too crazy but should still be very mild with alcohol.

Cams have come up several times. I am most familiar with small block Mopar. They very routinely have cams with LSA 107, 108 in a higher performance application. For gen 3, there is almost none below 112. I am wondering why that is, why they still sound good and rev with what would be a truck cam in a small block from a LSA perspective. I know theres a ton to the cam equation and I am not a cam guru by any shape or form.

I know the beauty of gen 3 hemis (apart from the incredible BGE block) is how great the heads are stock. My issue is by the time I buy cores for $1200-1500, have them gone thru, replace valves and springs, its getting close to what aftermarket ones run. for $3500 Blackbird is claiming to have turn key heads ready to go that I would expect are stronger and better than the already incredible 6.4 heads. A lot to consider, for sure!!! There isn't a ton of literature out on this engine, compared to older Mopar and certainly GM especially LS which is a contemporary. I do predict gen 3 hemi will take off and the aftermarket support is ratcheting up exponentially. I appreciate all the wisdom shared thus far!

https://www.youtube.com/watch?v=O_jkrntaJ3I is the video he's referencing

Lift is limited for two reasons , one is the length OEM lifter bore and lifter , if you have a cam base circle smaller than( don't quote me been a awhile) 1.56 the lifters will fall out of the plastic tray/retainer. on the other end of it is the location of the shafts and the tip of the valve , the arc of motion at .670 Gross lift loses contact with the head of the valve , Lash caps can only add so much to the contact area.
the other issue and it's more of a If you get there here's the next hill to climb , The OEM heads will only support 450lbs of spring pressure,

When we run the pedestal mount Jesel rocker system, we can add a spacer under the valve spring (and longer Valves) and you can go as high as .800 lift....Keep in mind you just added 5k for the rocker system and a minimum 2k-3k in specialty lifters.

Dave's partially correct, the other factor is it's an "under Square" bore/stroke combination , you'll see it also 3.9xx X 4.05 (5.7 Block) 39X CI Builds compared to 4.09/4.10X3.72(6.4 block) 39X CI builds with the same heads and camshaft.

For example ,3.937X4.05 = 394ci, while 4.10X3.72 =393ci , with Eagle heads on both , the 393 Peak HP will be roughly 10hp more at a higher RPM, Apache/BGE heads it'll be a difference of roughly 15 Hp , again this is example not absolute.

A comment on why All G3 cams have wide LSA ,

All of the current Cam offerings are geared towards Computer controlled engine management systems, tight LSA is hard to tune on the OEM systems.

Hughes Engines was the only one to offer new Non-EFI cams , some of their high lift cams had LSA's around 108-110, they stopped selling their G3 cams a few years ago, I guess they just didn't sell well. there's a guy on Ebay that sells reground Non-VVT cams , some of his grinds work great in carburetor applications.

The narrower LSA and large Exhaust valve pulls enough intake charge out at higher RPMs to effect how I tune an EFI G3 especially a OEM ECU/PCM , the NGC3(&4) is less effected but the GPEC(s) have more hidden emissions tables that don't like excess unburnt fuel........ while a Carb/MSD Hemi-6 doesn't seem to care. One of the G3 advantages over the G2 is the shallower valve angles don't pull as hard on the Intake charge coming in when you get above 65000RPMs , but it still pulls harder one the intake charge than a SBM or BBM , it's about the same as a 351C 4V , some of the more aggressive 351C roller cam profiles transfer over well to the G3 platform.....(just saying)

I've said before I prefer Eagle heads to Apache(in a NA build) this is one of the reasons, If I build a 392 for a 2014 Challenger, I can make more overall Power/Tq with 340CFM Eagles then I can 340CFM Apache/BGE

This is all great info gentlemen.

The prefix intake in a 4500 flange has me interested in carb form.To me if the heads are flowing 400 cfm the 4500 flange would be beneficial.I also run e85 that's available from the pump that always test good.

Keep the info coming so we all can learn please.

Here are some simple tips/things I've learned since building my first NA Gen 3 Hemi in 2010.

1. Blocks, all the G3 Hemi blocks can handle anything you want to throw at it for an NA combo. 5.7, 6.1, 6.4 Scat Pack, BGE or Hellcat. One of the motors I have is a carbed 357" 5.7 based motor with ported BGE heads on Nitrous that with a .036 jet fogger, is making about 1100hp. So don't get hung up on having to have a BGE block.

2. Heads, Ported Eagle, Apache or BGE heads work fantastic. I've been using Craig Thibeau, who owns Thitek for my cylinder head needs for a decade. He was the first in the Gen 3 market to develop his own aftermarket head called the Big Bear, about 2012?, which I own a pair and have been fantastic and make great power. But, I also have used his ported factory offerings and they all have been great. Eagles have a 2.10 dia. intake valve. Apache's and BGE's have a 2.14 dia. intake valve. You can also have larger valves put in the stock castings too, if needed. My ported BGE's have 2.18 dia. intakes in them. The aftermarket offerings are all pretty good, but again I'm partial to Thitek and they have various port/valve size versions to suit many applications. Feel free to reach out to me if you want contact info for him.

3. Rockers, bang for the buck, the stock valve train is very stable and reliable for what you want to do. They even have proven to handle plenty of power thru 1500-1600hp with power adder builds. I'd never talk anyone out of going T & D or Jesel for adjustable rockers, but they are a few bucks.

3. Camshafts, don't get caught on lobe center numbers, they are a resultant of the valve events design, not a design criteria. All the cams I've had were 112 or greater, for my NA combos. Keep the lobe lift to .400 /.410 max, which is about .650 lift. The stock rockers can't really handle much more than that with the sweep of the stock rocker. Pick your cam company you are most comfortable with and ride with them. Gen 3's are not magic, they're just another motor and any competent cam company can supply you a cam that fits the application.

4. Lifters, do yourself a favor and get the Johnson Short travel lifters with axle oiling #ST2356. They are the BEST hydraulic roller lifter for the Gen 3. BUT, when using short travel lifters, you need to measure every pushrod position for the length as the preload is only .030" +/- .005". And don't be shocked by having to order various different length pushrods. The last motor I just finished up had 6 different lengths needed, I use Manton for my Custom length pushrods.

5. Every NA comb I've had, at minimum peak HP was 7000 for my mildest combo to 7600 for my wildest combo. For a 700-750 combo, it'll probably be around 7200-7400 range. Shift at 75-7700 and you're rocking!

6. Intake manifold, depends on if you plan carb or EFI. The Ritter or Prefix Drag Pack Intake with a Dominator carb flange is my go-to 100% of the time. Unless you build enough motor and to want to venture into a tunnel ram, The Holley Hi-Ram is a great piece.

7. Crankshafts, I try to never go past 4" max on the stroke. Even at 4" stroke, due to the cylinder wall length, the piston skirts take a beating and there is nothing you can do about it, due to the piston sticking out of the bore at the bottom of the piston crank travel. Callies Compstar and Molnar Technologies are both great products.

8. Rods, any good H-Beam works well. Just like the crank, Callies and Molnar are my go to's.

9. Pistons, I'm a Diamond guy, but all the piston companies offer nice pieces. Pick your poison. If you plan on running alcohol, I'd go 14:1 easily on compression, On my gas applications, street / strip combos, I usually go 12-12.5:1. Run 93 on the street (when driving sane) and race fuel at the track and on the street (when beating on it). On race only gas applications, 14-15:1 compression.

10. Oil Pumps. Melling has plenty of offerings that work well.

Off the top of my head, these basics should help you. Enjoy!!

The bright side of the soft .650 lift limit (I call it a soft limit because you can do more but it gets really expensive really fast) is it is less critical than other engine platforms because the hemi flow at lower lifts is insane, there is nothing that can flow as much at .300 and .400 so what you are used to needing on other engines for a certain power don't apply here. An LS3 is the best readily available chevy LS head for example it has about 50 CFM on it at just .300 lift and .400 lift the hemi is outflowing it by 285 to 265 and even at .600 still has it by 10 CFM so if you had the same cam the hemi will start accelerating the air charge into the chamber at lower lift and that inertia will help the head flow more at peak lift in a real world dynamic situation. The common everyday BGE truck head still flows more than the LS7 factory CNC ported head and is about the same at higher lift and those only came in a few Corvette and Camaros. The low lift flow is one reason the LSA is wider than wedges, no point in flowing so much air into the chamber while the exhaust port is still open. The big tuning problem with MPFI is the fuel is the first thing in the chamber when the valve opens because the fuel is squirted on the back of the closed intake valve and if the exhaust is open the fuel flows (not all of it but a significant portion) out the exhaust then the ex valve closes and traps a lean mix in it but the exhaust O2 reading is still gonna show a normal A/F ratio, you mitigate this with wider LSA, same thing happens on a wedge but it is more dramatic in a hemi with it's great low lift flow.