600 HP 6.4 Hemi Apache Build — The Honest Parts List

TL;DR: 600 crank horsepower from a 6.4 Apache is 1.53 hp per cubic inch, and the 392 cannot buy it the way a small block does — with rpm. A factory 6.4 already turns roughly 3,970 ft/min of mean piston speed at its 6,400 rpm redline, so a naturally aspirated 600 has to come almost entirely from airflow per revolution: CNC heads, a real camshaft, and an intake manifold. Two of those three are on our shelves. The blower path reaches the same number on a stock long block with a fuel-and-clamping budget instead of a machine-shop budget, and for most readers it is the correct answer.

What 600 HP Actually Costs on 392 Cubic Inches

The 6.4 Apache is a 4.090 in bore on a 3.72 in stroke — 391 cubic inches, sold as a 392. Factory output on a Scat Pack or SRT 392 is 485 hp (confirm against your model year), so 600 is a 115 hp ask, about 24 percent over stock.

That sounds modest until you write it as an output figure per cubic inch and set it beside the builds we have already costed out.

The last two rows are the article. The same 600 horsepower is three genuinely different purchase orders depending on which one you pick, and the gap between those three is far larger than the gap between brands inside any one of them.

The 392 Runs Out of RPM Before It Runs Out of Head

This is the fact that makes a 392 build different from a 383 or a 347, and almost nobody states it.

Mean piston speed is stroke times two times rpm, divided by twelve. On a 3.72 in stroke at the factory 6,400 rpm redline that is about 3,970 ft/min. Take the same engine to 7,000 rpm chasing the last 60 horsepower and you are near 4,340 ft/min, which is where ring, bearing and rod-bolt life stop being measured in seasons.

A 500 hp 383 gets a meaningful share of its number by revving to 6,200. A naturally aspirated 600 hp 392 does not have that lever, because Chrysler already spent it. Every horsepower over stock has to arrive as more air per revolution, which means three purchases in this order:

1. Cylinder heads that flow past the factory Apache casting
2. A camshaft with the duration to use them
3. An intake manifold that is not the factory active-runner piece

We stock the first two. The third does not exist in this catalog, and that omission is the most important thing on this page — it gets its own section below.

Start at the family page: browse Gen III Hemi engine parts and filter to the 6.4 Apache tag before anything else, because the 5.7 Eagle, 6.1 SRT, 6.4 Apache and 6.2 Hellcat share a family name and almost no parts.

Path A: The Blower, and Why It Is Usually the Right Answer

If the goal is the number rather than the method, the supercharger path gets there on a stock 6.4 short block.

A 2650-class blower on a 392 is not working hard at 600 crank horsepower. Take boost level and published output from the kit's own documentation. What matters here is that the blower path moves spending away from machine work and toward four supporting items:

• Head clamping. CPP-HEMI64-HARDWARE-ARP-01, the ARP Hemi head stud kit. Our own listing says it plainly: the studs exist for 6.4 Apache head-bolt thread pull on boosted builds. Factory head bolts are torque-to-yield and are not reused.
• The head gasket. CPP-HEMI64-GASKET-CMT-04 is the Cometic MLS row written for stroker and boost duty. CPP-HEMI64-GASKET-FPR-01 (Fel-Pro HS26284PT) is the OE-replacement MLS set and is the right part for the N/A path.
• Ring package. CPP-HEMI64-RINGS-TS-02, the Total Seal gapless second-ring set — but only if the short block is opened at all. On a stock long block you are not opening it, which is the entire point of this path.
• Fuel. Worked below.

If you are not opening the engine, you are not buying pistons, rods, bearings or a crankshaft — and most 392 build lists will sell you a rotating assembly this path does not need.

Path B: The Naturally Aspirated 600, Honestly

Three head choices exist for the Apache:

Two notes before you buy.

First, none of these three rows publishes an intake runner volume, a chamber volume, a flow figure or an assembled spring rating. The titles say "CNC" and stop. On a 600 hp N/A build the chamber volume alone moves static compression by most of a point, so confirm chamber cc and assembled state with us before ordering. You cannot spec this build from our product titles as they currently read — that is a data gap on our side, not a judgement call on yours.

Second, the third row is labeled in a way worth knowing about. It is titled as an Eagle head — 53022AE — while sitting on a 6.4 Apache row, and its own application note says Eagle, 6.1 and 6.4 Apache castings are not interchangeable. The row contradicts itself. Treat it as an item to confirm with us before ordering — and an OE-grade casting is not what a 1.53 hp/ci engine needs regardless.

The Camshaft Is a Phaser Decision Before It Is a Lift Decision

The 6.4 Apache is variable-cam-timing equipped. Some applications — Ram HD, and automatic-transmission cars, depending on model year and gearbox — also carry MDS cylinder deactivation. Those are two different systems, they fail differently, and only one of them should ever be deleted. That is why all three Apache cam rows read the same way:

Keeping the phaser functional is the right default on a street 392. A VCT-retaining grind lets the calibration hold cam timing for low-speed torque and sweep it for top end; giving that up costs driveability for a number you read once.

Two honest cautions on this table.

The Thumpr is a sound-first grind. It is ground for idle character, with a wide lobe separation and deliberately asymmetric overlap. It is a good cam for a truck that needs to announce itself and a poor cam for the top of a naturally aspirated power band. At 1.53 hp/ci you want duration at .050 — and this catalog does not print duration at .050 on any camshaft row. The titles carry brand and stage and nothing measurable.

"Stage II" is not a spec. A genuine 600 hp N/A 392 wants a grind in the neighborhood of 240 degrees at .050 or more, matched to the head you actually buy. Whether BTR's Stage II clears that bar is not answerable from our data, and a build list that pretends otherwise is guessing on your behalf. Ask for the cam card before you order, from us or from anyone.

Whatever grind you land on, the cam does not go in alone:

• CPP-HEMI64-VTRAIN-MPR-02 — Mopar Hellcat-spec dual springs, PN 5037428AB. The standard upgrade once lift passes the OE beehive's window.
• CPP-HEMI64-VTRAIN-COMP-01 — COMP beehive set, the lighter alternative for a milder grind.
• CPP-HEMI64-VTRAIN-COMP-03 — COMP pushrod set. Factory pushrods are the known weak link once spring pressure rises.
• CPP-HEMI64-TIMING-CLY-04 — Cloyes full Hemi timing master bundle: primary chain, secondary chain, tensioners, guides and phaser in one line.

That last one deserves its own sentence. The Gen III Hemi runs two timing chains, and the front cover is already off for the cam swap. Buying the primary set alone (CPP-HEMI64-TIMING-CLY-01) and leaving a stretched secondary in the engine is how a good cam job comes back apart. Compare the timing components rows and buy the bundle.

MDS: Delete It or Keep It, but Decide Before You Order the Cam

If your Apache has MDS, the collapsed-lifter failure is the one that ends engines — codes, then a dead bank, then bent pushrods. We carry the full delete stack:

A complete delete is lifters, tray, plugs, harness and a calibration. The tune is not in the box on any of these rows. And deleting MDS is not the same as deleting VCT — keep the phaser.

Fuel: Worked, and Why the N/A Build Should Not Buy Injectors

Take 600 crank horsepower at a naturally aspirated gasoline BSFC of about 0.50 lb/hp-hr. That is 300 lb/hr total, 37.5 lb/hr per injector at 100 percent duty cycle, and about 44 lb/hr at a sane 85 percent. The factory 392 injector's published flow rating — confirm it against the manufacturer's data — covers the naturally aspirated build with margin.

Run the blown case at 0.58 BSFC and the same arithmetic gives about 51 lb/hr at 85 percent duty — right at the factory injector's edge on pump gasoline. Move to E85 at roughly 0.75 BSFC and the requirement is about 66 lb/hr, near 700 cc/min, and now CPP-HEMI64-FUEL-ID-02 (Injector Dynamics ID1050x) is the right part rather than an upsell.

So: N/A 600 keeps the factory injectors. Blown 600 on pump gas is marginal and should be measured, not assumed. Blown 600 on E85 buys the ID1050x. CPP-HEMI64-FUEL-ACF-01, the Accufab 105 mm billet throttle body, is a real part but a top-of-the-band one — it will not rescue a build that is short on head flow. Browse fuel injectors after you have decided fuel type, not before.

What This Catalog Cannot Currently Sell You

Stated plainly, because a build list that hides its gaps is not a build list.

1. There is no naturally aspirated intake manifold for the 6.4 Apache. Both rows typed as Intake Manifolds under this engine are supercharger kits. The N/A path's third-largest airflow purchase has no SKU here.
2. There are no Gen III Hemi connecting rods — not for the 6.4, not for any Hemi. Every connecting rod row in the catalog is a diesel row. The 392's powdered-metal cracked-cap rods are the accepted limiter on serious boost builds, and we cannot sell the fix.
3. There are no Hemi main studs, in any displacement.
4. There is no Hemi harmonic balancer and no Hemi flexplate or flywheel. Across 196 Hemi rows there is zero balance attach — and a stroker crank is precisely the part that changes balance.
5. No headers and no rocker arms.

One data defect worth knowing while you shop: all four Hemi stroker crank and rotating-assembly rows — Callies DragonSlayer CPP-HEMI64STR-CRANK-CLS-01, K1 -02, Arrington -03, Indy -04 — are typed Timing Components. A crankshaft filed under timing will not surface in faceted search where a buyer looks for it.

The 426-Class Stroker, If You Are Opening the Engine Anyway

The Callies row is a 4.05 in stroke forged crank. On the Apache's 4.090 in bore that is 426 cubic inches — the number on a badge Chrysler has been selling since 1964, and a real one this time.

At 426 ci, 600 horsepower is 1.41 hp/ci instead of 1.53. Same cam, same heads, more margin, and the power lands lower in the rev range, which is exactly where the piston-speed problem lives. Two of the four rows come as complete assemblies (CPP-HEMI64STR-CRANK-ARR-03, CPP-HEMI64STR-CRANK-IND-04), and that matters, because the two crank-only rows leave you sourcing connecting rods we do not stock. Confirm complete assembly contents on all four before ordering — our own rows say so.

Supporting parts for an opened short block: CPP-HEMI64-PISTONS-DMD-02 (Diamond forged boost) for the blown path or -MAH-01 / -JE-03 / -WIS-04 for N/A, CPP-HEMI64-RINGS-TS-02 for rings, CPP-HEMI64-HPMAIN-KNG-03 and CPP-HEMI64-HPROD-KNG-04 for King HP bearings, and CPP-HEMI64-OIL-MEL-01, the Melling M340 pump. Start at pistons and engine bearings, and match everything to one bore size before placing a single order.

FAQ

Is 600 hp possible on a stock 6.4 Apache short block? On boost, yes — a 2650-class blower makes it without opening the engine, provided head studs, gasket and fuel are handled. Naturally aspirated, 600 needs CNC heads, a large camshaft and an intake manifold, and it lands very near the factory rpm ceiling.

Do I have to delete MDS to run a performance cam? Not necessarily. All three Apache cams are VCT-compatible hydraulic rollers and do not require an MDS delete on their own. If the engine has MDS and you are already inside it, deleting is the durable choice — but the delete needs lifters, valley tray, galley plugs, harness and a calibration together, not just lifters.

Should the VCT phaser be locked out? Not on a street 392. Variable cam timing is the reason the engine has both bottom-end torque and top-end power. Keep it and buy a VCT-retaining grind. MDS delete and VCT delete are two different jobs.

Do I need bigger injectors for a 600 hp 392? Naturally aspirated on gasoline, no — the arithmetic puts the requirement near 44 lb/hr at 85 percent duty and the factory injector is above that. Supercharged on gasoline it is marginal and should be measured. On E85 you need roughly 66 lb/hr, and the ID1050x is the correct part.

Are ARP head studs required? On the boosted path, yes — 6.4 head-bolt thread pull is the reason that kit exists. On the naturally aspirated path, new torque-to-yield factory bolts and an MLS gasket are sufficient. Factory head bolts are single-use either way.

Can I stroke a 6.4 to 426 cubic inches? Yes. A 4.05 inch stroke crank in the 4.090 inch Apache bore gives 426 ci, which drops the target from 1.53 to 1.41 hp per cubic inch. Two of the four rows are complete rotating assemblies; the two crank-only rows require connecting rods that are not in this catalog.

Why does a cam swap need both timing chains? The Gen III Hemi uses a primary and a secondary chain. The front cover has to come off either way, so replacing only the primary leaves a worn secondary in an engine that is now making more power. The Cloyes master bundle covers both, plus tensioners, guides and the phaser.

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