Chevy Craft, Camaro Craft, Chevelle Craft, yes, we here at CC have been accused of that from time to time. Some might even say all the time, though our archives prove otherwise. However, we do admit to not being as well versed on other manufacturers' offerings as we are with the stuff from Chevrolet. Case in point is the small-block, known as the Chrysler LA engine. We all know you can make really big power with a 440 or 426 Hemi, but we weren't fully aware of the power potential lurking within the thin wall castings of the LA, a lightweight evolution of the earlier A engine, hence the L prefix.
The Chrysler LA engine went into production in 1964 as a replacement for the A engines. The main difference between the two is the cylinder head configuration. The A engines had polyspherical combustion chambers with the intake valve canted toward the intake manifold. Unlike the Hemi heads, the poly heads used a single shaft per head to mount the rocker arms, likely done as a cost-cutting measure. Hemi engines used separate shafts for the intake and exhaust rocker arms.
The Chrysler LA engine was designed with wedge-shaped combustion chambers, and the intake and exhaust valves were arranged in a row. The simpler valvetrain design allowed for a more compact cylinder head that gave Dodge and Plymouth engineers the clearance they needed to drop a V-8 into the narrow confines of the Valiant and Dart engine compartment. As an added bonus, the thin wall castings of the engine block added up to a 50-pound weight savings over the A engine-you could have the performance advantage of V-8 power in a small car without the weight penalty of a heavier casting.
The first Chrysler LA engine was the 273, which made its debut in 1964. It was followed closely by the 318 in 1967, the 340 in 1968, and the 360 in 1971. Of all these configurations, the 318 and 360 engines survived the longest, soldiering on until 2002. Note that the A engine family was being phased out during the time that the LA engines were rolling out, so it's possible to see a poly 318 in 1967 alongside an LA 318. Throughout their run, the LA 318 and 360 engines saw several updates, notably the introduction of throttle-body fuel injection and roller cams in the '80s, culminating with the Magnum versions in 1992 and 1993, respectively. The LA V-8s were phased out by 2003, being replaced by the 4.7 V-8s in the Jeep Grand Cherokee and the new Hemi engines.
Still, a 30-plus-year production run means small-block Chrysler engines are readily available for building. Though largely overshadowed by their big brothers, the B and RB engines (383, 440), there is plenty of performance potential in the LA. We talked with several experts to get their build ideas, and the overwhelming consensus was to build a stroker. It turns out you can put a 4-inch-stroke crankshaft into any LA block without clearancing and really pump up the cubic inches. Of course, more cubic inches mean more power, right? Interested? Read on...
LA Engines By the Numbers
Years in production: 1964 to 2003
Bore spacing: 4.46 inches
Deck height: 9.60 inches
Firing order: 1-8-4-3-6-7-5-2
No. 1 cylinder on driver side front/distributor turns clockwise.
Random factoid: Did you know the 3.9L V-6 and 8.0L V-10 are also based on the LA architecture?
Displacement Bore Stroke 273 (4.5L) 3.625 3.31 318 (5.2L) 3.91 3.31 340 (5.6L) 4.04 3.31 360 (5.9L) 4.00 3.58 Hughes $5,000 Stroker Description PN Price Engine block and machining N/A $500.00 Stroker kit HUG318 $1,600.00 Hydraulic flat-tappet cam Take your pick $160.00 Hydraulic lifters HUG5001 $44.00 Custom-length pushrods N/A $225.00 RHS heads complete (stainless 2.02/1.62 valves) HUG20301C $1,150.00 Rocker arms and shafts HUG1506-S16 $440.00 Rocker shaft hold-down kit HUG7440 $85.00 Gasket set HUG3010 $58.00 ARP fasteners HUG7334 $130.00 Edelbrock RPM Air-Gap HUG5303 $259.00 Holley 750-cfm carburetor N/A $400.00OK, that totals just over $5,000, and no, we didn't include valve covers, timing cover, and oil pan, but hopefully you'll be able to reuse that stuff from your donor engine. Still, we think this is a great price for Chrysler stuff. Even better: The Hughes guys told us this combination will make damn close to 500 hp. Put that in your Duster and smoke it.
Supercharged 318
We spoke with Bob Woods, owner of The Supercharger Store, to get his take on a 318 build. Coinci-dentally, he was just finishing assembly of a 318 build for our sister magazine Mopar Muscle. The goal was to make enough power to run low 11s in a '67 Valiant but still generate 12 inches of vacuum at idle, get 16 to 18 mpg, run A/C and power brakes, and burn 91-octane gasoline, not uberexpensive race gas. You'll have to get the specs and build details in upcoming issues of Mopar Muscle, but Woods whispered the dyno numbers to us: On the motor, this combination made 370 hp and 349 lb-ft. Boosted with 14.5 psi from a Procharger P1SC, this stock-stroke engine made 662 hp and 587 lb-ft at the crank. Woods was especially proud of the low-end torque this combination generated. At 2,500 rpm, the dyno read 305 pounds of twist.
For a more budget-oriented build, Woods recommends the following:
• 0.030-over 318 short-block-reuse the stock crank and rods
• Speed-Pro pistons: TRW-L 2329F-30 ($395.12)
• Hughes-built RHS heads: HUG 20301B ($975.00)
• Hydraulic flat-tappet cam specs: 223/232 duration at 0.050, 0.540/0.571 lift (using 1.6:1 rocker arms), 113-degree LSA
