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The LA-Based Four Cylinder Racing Engine

View from right side; and dressed engine
A4 LA based four cylinder racing engineLA based A4 four cylinder engine

The A-4 is a racing engine based on the LA 5.2/5.9 V8, available from Mopar Performance.

There are three major blocks:

  • P5007466 Midget race block (includes special features for midget racing, e.g. special cooling passages with
  • P5007467 drag race block (v8 flywheel housing for RWD transmissions) for P5 Hemi head
  • P5007636 wedge-head race block (fits W8/W9 heads and V8 flywheel housing for RWD transmissions)

These A-4 aluminum blocks use many Chrysler small block components for assembly and feature corrected valvetrain geometry (an endemic proplem with the LA since it was designed) and a shorter deck height. These engines, being sold by Mopar Performance, meet MP’s durability and safety standards, and were dyno tested and factory sealed for consistent output.

The midget block was listed at $6,121 (we found it for $5,600) in 2010, with cast iron sleeves, billet steel or billet aluminum main caps, a main cap stud kit, and mounting hardware. It had an unfinished 4.130 in. bore with 8.40 in. or 9.00 in. deck heights; it accepted W9 raised-port aluminum cylinder heads for sprint or Midget racing.

The drag race block listed $5,217 in 2010 (and was sold retail for under $5,000). The wedge-head race blocks, listed as being designed for USAC Midget and drag racing, ran $6,644, list, in 2010. Both came with steel billet caps, ductile iron sleeves, and a hardware kit.

Midget motor dressed and ready to install. Note in the two "dressed" photos: cam driven dry sump oil pump system and aluminum oil pan, crank driven water pump and lack of a distributor. This uses a Distributorless Ignition system (shown with the W8 head, not the HEMI). Headers shown are for a midget race car.

The block top deck is extra thick to allow for O-ringing and forced induction. The racers that are currently utilizing this engine are walking away with all the marbles over the GM "Iron Duke" based engines.

Coupled with a Hewland EGT series transaxle this engine, when installed into a lightened Neon (prepped similarly to Gary Donovan's 10 second Reliant), should (opinion, not fact) be able to dip into the mid to low 9 second ET range in the quarter mile due to lighter potential weight and higher rpm capabability.

View from the front, back, and top of the block (unmachined). The rear view shows the conventional rear wheel drive flange for using a conventional A727, A833, or other large Chrysler pattern aftermarket transmission.
 P5007961 Full Engine (W9 heads)
Rated power350 hp@ 7200; 265 lb-ft @ 6,000
Redline8,500 recommended; 9,000 max
Displacement162 cid (38 cc combustion chambers)
Compression15:1 (methanol)
Crank and camScat crank, roller cam with 60 mm bearings

A pair of turbos, sequentially fed through proper charge air cooling, should push the motor in this application, to over 600 hp and have FAR more durability that a 2.2/2.5 or 2.0/2.4 engine and a higher rpm range.

The Hewland transaxle mentioned earlier is $16,000 - the price of being the best. A race car of this type costs anywhere from $35,000 to $85,000 to be competitive. NASCAR cars cost from $80,000 to $160,000 each or more.

When this article was written, the cost for the block (semi machined) was about $1000 and the Hemi head was about $800 bare and semi-machined also. These pieces were released in the 2002 Mopar Performance catalog. The cool looking magnesium valve covers were on page 116.

As far a this engine ever being a "production car piece"... it was intended strictly for racing, and does not meet EPA standards for street engines.

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