Last month, we chronicled the buildup of a small-block 383 Chevy using a cast 400 small-block crankshaft, all with the goal of making 500 lb-ft of torque. If you will recall, our original goal was to make a lot of torque; we were not concerned with horsepower. As we explained last month (Torque Terror, Oct., 2000) because this motor is slated for a 4x4 project that is currently underway, we felt that there was really no use for a high-horsepower engine when the end result of this truck project would be a strong on- and-off-road performer.
The combination of parts we selected was to serve our intention of producing 500 lb-ft of torque. To aid in our parts selection and dynamometer testing, we enlisted the help of engine builder extraordinare John Baechtel at Westech Performance in Mira Loma, California. When we initially set out to build this torque package, we also wanted to do it on a budget. Granted, the parts we used cost far more than $1,000, but to achieve the torque figures that we desired, some exceptions had to be made.
Because we wanted to make this an affordable torque motor, we called Summit Racing and asked the company to supply us with the bulk of the motor parts. Summit Racing, long recognized for its excellent mail-order engine combinations, was only too willing to accommodate us in our quest.
Engine Testing
Upon the conclusion of the initial engine buildup, it was time to get the motor set into Westech's dyno cell room. Once it was set into place, several different things had to be accomplished before we fired up the motor to break in the Comp Cams 256H hydraulic tappet camshaft. For starters, Steve Brul at Westech pre-oiled the motor to get adequate lubrication in the top half of the long-block assembly so that when we fired up the motor, it would not be dry, which would damage the internal parts.
After pre-oiling the motor, we set the initial timing. Turning the motor over and using a timing light, Steve set the initial timing at 10 degrees BTDC (before top dead center). Because of Westech's vast engine dyno testing, and since we were using an MSD HEI-type distributor and ignition system, Steve knew that the heavy-duty mechanical advance weight springs on the MSD distributor would have to be changed to a set of lighter springs to allow themechanical advance to come in earlier. The total timing was set at 34 degrees.
Topping our 383 small-block is an Edelbrock Performer RPM dual-plane intake manifold and a 750-cfm vacuum secondary Demon carburetor. After the initial camshaft break-in, while using standard 30W oil, we let the motor run on the dyno for approximately one full hour before making any torque pulls or placing a load on the new motor. After the hour break-in period, all of the oil was drained and refilled with 10W40 oil and a fresh oil filter was installed.
Making our first pull on the Westech dyno yielded two things immediately. First, the carburetor was jetted far too rich on both the primary and the secondary. After taking fuel out of the mix by downsizing the carb's jets, John ran the motor again. From the initial reaction and the signs that showed total torque and total horsepower, John could tell that we were nowhere near our 500 lb-ft estimation. We swapped out the 750-cfm vacuum secondary Demon carburetor for a more aggressive Demon 750-cfm double-pumper. After several dyno pulls, we were still not anywhere near our 500 lb-ft goal, but the torque curve numbers were climbing, so we were optimistic.
After nearly 10 dyno pulls and countless hours playing with the timing, the carburetor jet sizes, and numerous carburetor spacers, the best we could muster in torque was 442 lb-ft at 3,700 rpm. While we certainly did not meet our 500 lb-ft goals, one interesting side note is that this motor was able to make 375 hp at 5,200 rpm. Granted, that doesn't seem like a lot of horsepower, but take into consideration that this camshaft is only one grade higher than a stock duration and lift camshaft, thus, the engine's output is all that more impressive.
One other factor that also seemed quite interesting to the guys at Westech was that this motor made 400 lb-ft of torque consistently throughout its powerband. While that may seem inconsequential to some, if you drop this motor into a well setup 4x4, you'll have truly powerful machine that will have enough torque for any driving situation.
Combine this potent powerplant with the right transmission and differential gears, and you have a real back-pinning combination. So, while we have not accomplished our 500 lb-ft goal yet, do not fret. This is just the start. We plan to swap out the heads for smaller combustion chamber models and smaller valves, probably in the 1.94/1.50-inch range, and maybe 1.6-inch roller rocker arms to increase the overall lift of the practically stock camshaft. Hopefully, these minor modifications will get us to our 500 lb-ft goal. Stay tuned; we will be back with more in the future.
Prior to engine fire-up, we filled the motor with 30W oil. After the camshaft break-in period of roughly 30 minutes at varying rpm - not exceeding 2,500 rpm - we drained the 30W and refilled the motor with fresh 10W40 and installed a new oil filter. | 
As an added precaution against premature wear upon initial break-in, Steve Brul at Westech Performance likes to use this Oil Extreme lubrication, which adds an extra barrier of protection against possible metal-to-metal friction. | 
Steve pre-lubes every motor before firing it up. This special MSD pre-oiler operates off a standard 3/8-inch drill and fits inside the distributor opening. Once the fresh oil worked its way up into the top portion of the motor, the pre-oiler was removed and replaced with the MSD HEI ignition system. For those of you without the MSD pre-oiler, use an old distributor and simply remove the guts and attach your drill motor to the top of the distributor driveshaft. |
Based upon Westech's experience with the MSD HEI distributors, and knowing our 500 lb-ft of torque goal, the stock mechanical advance springs were replaced with the lightest possible springs that MSD offers. This allows the mechanical advance to come in at a faster rate, thus improving overall torque and horsepower. | 
Steve set the initial timing at 10 degrees BTDC and the total timing at 34 degrees. Numerous changes in initial and total timing were not good enough to yield us 500 lb-ft of torque, but overall, the 400 lb-ft we produced throughout the operating band of the engine is respectable. | 
To further improve upon low-end torque, we ran the motor in the dyno cell room, with headers and an exhaust system, thinking that this would also produce higher torque peaks. The combination we used included 1-3/4-inch headers with 3-Series Flowmaster mufflers. Smaller primary tube headers would also have produced more torque, but not 60 lb-ft, which is where we fell short. |
That's John Baechtel at the helm of his dyno machine. If you have the time, the money, and the motor, you can work anything out on John's toy. Plus, if you are tuning for the best possible horsepower or torque applications, Westech's dyno facilities are superb: These people live, breathe, and love to test motors. Consider Westech an adult playground for power. | | |