Despite the overwhelming influx of EFI, the carburetor (sometimes referred to as the "toilet") stands as the preferred choice. Hot rodders are known as a resourceful lot and the prevailing mothers of invention, but in this case, the high-performance arm of the very people who developed the EFI system for the LS1 engine are the curious, can't-leave-it-stock neurotics.
Lucky for us, the gearheads at GM Performance Parts seem to have beaten the aftermarket at its own game. Edelbrock, who made its name on the intake manifold, is the only supplier to date who has stepped forward with a carburetor conversion for the LS1 ("Sand Paper," page 66).
Now that the new millennium small-block is an accepted form of re-powering, and with the new 6.0L LS2 as well as the 505hp LS7 being offered as crate motors, the carbureted iteration will undoubtedly be lowered into more engine compartments than you can shake a camshaft at. No electronics or computer to worry about--just hook up the loud pedal linkage, tweak the distributor, and blast into the ozone. Racers (e.g., NHRA, IMCA, USAC) who are bound by rules that forbid computer controls now have a compact, vibrant, and robust alternative to the traditional small-block.
In anticipation of this prospect, Ed Taylor outfitted a stock displacement (346ci) LS1 crate engine with a livelier camshaft and CNC cylinder heads, and applied the GMPP intake manifold and a Holley HP 750-cfm carburetor. The mechanical fuel pump and aftermarket distributor were driven off an eccentric and a gear on the camshaft, respectively (see image). Further, the headers fitted to the test rocket were Kooks with 1 7/8-inch primary pipes dumping into Flowmaster 2 1/2-inch Super 40 muffs. The camshaft is Crane Cams piece (PN 144HR00061) featuring 222/234 degrees of duration at 0.050 inch, a 0.551-inch lift on both valves, and 112 degree centerline.
As we have witnessed with our own crate demon, the LS1-engine family offers excellent power production in a lightweight package (395 pounds with accessories and cast-iron exhaust manifolds). And moxie? Boy, does it flat ooze durability. Taylor's whipping dog has about 700 pulls on it (1,400- to 6,500-rpm range), 130 of 'em under a Magnuson blower making nearly 600 hp and still not a wisp of blow-by.
With the nylon OE intake manifold, a GM Hot Cam, and CNC cylinder heads this engine produced 492.9 hp at 6,200 rpm and 459.7 lb-ft of torque at 4,900 rpm. The numbers from the carburetor combo impressed even the GM engineer who designed the Gen-3 heads, as they were never meant for full wet flow. In EFI form, the fuel sprays down on the cathedral roof of the port and toward the intake valve. Let's take a peek over Taylor's shoulder as he turns the screws at Kenny Duttweiler's dynamometer and see how well the Fred Flintstone Conversion faired against the infinitely adjustable medium of electronic fuel injection.