It's been a few months since we updated you on our resident big-block project, but rest assured the 460 crate engine is making great progress.

Just to recap, you may recall that soon after the 428 blew its guts at mid track, Victor Silva made the decision to put a Ford Racing 535HP 460 crate engine between the shock towers of the '69 Mach 1. Thinking that a FRPP built and dyno tested crate engine would be a solid investment we headed to the track to make a few maiden passes. Deja vu struck on the second pass, as the 460 ground to halt shortly after the eighth mile. A deeper look revealed that a timing gear bolt had sheared, resulting in the valves giving the pistons a $5000 goodbye kiss.

Fortunately FRPP was willing to overlook their "no warranty" policy, and replaced the motor with no questions or hesitation -a move that makes us think ours wasn't the first 460 to bite the dust.

With 460 number two back in the Mach 1, Victor was ready to start the 2001 NHRA Craftsman Bracket racing series -a popular west coast series in which our Mach 1 runs under the Sportsman class.

Understandably a little gun shy, Victor decided not to push the 460 to its limits, but rather keep the shift points at a mild 5800 rpm and concentrate on consistent ET's. The 460 responded with fairly consistent 11.60's at 117mph.

While the mid-eleven second ET's were nice to see, they were nowhere near the full potential of the 535 HP crate engine. With the 60ft times at a mediocre 1.70, we knew there was room for improvement.

One other area where we speculated some potential for power gains was in the induction system. We were initially running a 750cfm Barry Grant Silver Claw. Thinking that this was not enough air for the hungry 460, we sold the carb and stepped up to Barry Grants big-gun, the Race Demon.

In "out of the box" configuration, at 825 cfm, the Race Demon dropped ET's down to 11.50's @ 117-118 mph. Jetting changes and we trimmed down another tenth. However we were surprised that changing to the gold venturi sleeves (975 cfm) resulted in no changes. We speculated there was an airflow problem to the carburetor due to the height of the motor.

The position of the 460 in the relatively tiny '69 engine bay, prevented us from using an air-filter. With the hood shut, the carburetor was a mere 1.5" from the underside of the hood scoop on the Mach 1.

Victor experimented with methods to better direct airflow into the carb. Ultimately the solution was to unbolt the small Mach 1 hood scoop, and use a 6" diameter air cleaner and filter which protruded several inches above the hood line. The result was big, 11.25 at 121 mph, a gain of nearly two tenths and three mph. Stepping up even more, to the 1025 cfm (black venturi sleeves) slowed the car down slightly, confirming that 975 cfm is about optimal for the FRPP 460 crate motor.

Still disappointed with the 60ft times, we spent considerable effort in analyzing the way the car launched. Victor noticed that the engine displayed a mild but long bog when launching, almost as if the engine was not developing full power in first gear.

After jetting the Race Demon up and down, playing with the venturi diameter, and also trying various tire pressure and Cal Trac bar pre-load combinations, we turned to the more fundamental matter of fuel delivery. After determining that the fuel pump was supplying adequate volume and pressure, we figured the only other problem might be temporary fuel starvation in the secondary float bowl.

We threw on a set of jet extension, and voila... a neck-snapping 1.52 60ft time! A $5 solution which rewarded us with three 11.06 @ 121-122 ET's in a row, with no change to the 5800 rpm shift point, and launching by flashing the converter to its 3000 rpm stall point. Even more impressive was that these runs were all during a bracket event with air temps in the low 90's.



With the bracket racing season nearing an end, we're looking forward to a test and tune session where Victor has promised to put aside his fear of grenading another motor, and pushing the 460 a little harder to see how deep in the 10's we can go! We also are looking to schedule a chasis dyno session to see just how much power we're getting to the wheels.

We'll keep you posted.

Source:
Demon Carburetion
1450 McDonald Road
Dahlonega, Georgia 30533
USA
http://www.barrygrant.com

Phone: (706) 864-4712
24 Hour Fax: (706) 864-2206