Crate Engines

The crate engine has become a player in short-track racing. In most cases, the track or series limits the engine selection to that of one manufacturer, but there are a few cases where attempts are being made to bring in multiple crate engines.

One attempt is being made in the FASTRUCK Series. Promoter Bobby Diehl brought in the General Motors' ZZ4 crate engine and decided to see what he could do to get the other manufacturers involved. With the help of some willing competitors, Diehl has taken steps to find out.

Earlier this year, an engine was borrowed from teams running each type-Chevrolet, Ford, and Dodge. They were taken to the engine dyno of Richards Racing Engines in Haines City, Florida. The Chevrolet went into the cell first, followed a few weeks later by the Ford. The Dodge, which required a set of headers that took some time to acquire, was last to visit.

The idea was to get the lay of the land on the important numbers. Each manufacturer provides this basic information to its customers, but those numbers generally pertain to the four-barrel carburetor. This series mandates a two-barrel carburetor, so there would be some difference in the performance numbers. The intent was to find out what needed to be done to get the engines to perform within a few horsepower or a couple of pounds of torque.

Scotty McLendon of McLendon Carburetors was an active participant in the testing. His carburetion knowledge gave insight into the changes needed to get the figures in the ballpark.

The majority of the testing used the BG Fuel Systems Demon two-barrel that was unveiled late last year. For ease of comparison, the removable sleeve (RS) model was selected. The carburetor's role in the engine's performance could be changed in minutes by simply pulling out a sleeve of one size and inserting a sleeve of a different size.

Chevy Test The ZZ4 crate engine (PN 24502609) is among the most popular engines available for racing. Most of the sanctions that mandate the crate engine chose the ZZ4 for a number of reasons. With the steel roller tappet camshaft (0.474-inch intake/0.510-inch exhaust valve lift), the engine made 355 hp at 5,250 rpm and torque figures in excess of 300 across the range. However, that was utilizing the four-barrel carburetor, so the figures were tossed out.

In the first test, the 500-cfm Demon two-barrel was fitted with silver (1.373) sleeves. Using 79 jets and 34-degree timing, the first test was conducted with peak horsepower at 5,900 rpm (see Figure 1).

After the first test, the carburetor was removed to change the sleeves. The jet size was changed to a 77 jet, and the green sleeves (1.28) were inserted. This test drew the numbers down with the engine recording its peak horsepower of 307 at 5,700 rpm (see Figure 2).

A final sleeve change brought the red (1.4) big sleeves into the carburetor. The jets were changed to 81. There was no change in timing (see Figure 3).

Bring on the Ford The selected Ford engine was the M6007A351E (forged pistons). This 351ci engine was pulling 385 hp with headers and a 785 carburetor. It featured a single plane Victor Jr. intake and the 5.8L Sportsman II race block.

The BG carburetor was bolted onto this engine, which proved itself stout right from the start. Using the silver sleeves, 78 jets, and 36 degrees of timing, it was a horsepower hero (see Figure 4).

The swap in sleeves was made to the green sleeves. In the process, torque and horsepower figures increased. The horsepower numbers kept growing to the 6,000-rpm range, so the peak may not have been realized in this test (see Figure 5).

The final test for the Ford engine came with the insertion of the red sleeves. This engine showed differences, but really started picking up after 4,500 rpm, hitting 380 hp at the 5,400-rpm range, a favorable range for many of the competitors (see Figure 6).