RDI Street 392 Crate Motor - Wicked Windsor In A Box, Part 2

This factor in itself is worthy of mention. Last month I said a motor that won't repeat each power run closely makes a poor dyno test mule. This RDI unit would deliver curves that laid one over the other time after time. Out of faint hope more than anything I suggested to Kenny we try 32 1/2 degrees total timing. Normally a 1/2 a degree is of no consequence especially as it is difficult to turn a distributor by just half a degree. However with the minimal scatter the Performance Distributors unit was giving and the micro adjustment changing by 1/2 a degree was no problem.

And, yes, I liked the results--501 hp. The magic 500 barrier was now broken. By utilizing the 1/2-degree timing capability the RDI motor returned 500-plus hp pull after pull. At this point we could safely assume all the power possible had been wrung out of the motor via jetting and timing. The WC Holley had delivered extremely well. Even though it is a race carb it idled smoothly and was very responsive. Also the brake specific fuel consumption of this motor with the Holley was exceptionally good.

To make the point a part throttle test to simulate a loaded half-ton truck (5,500 pounds gross) going down the freeway at 70 mph was done. The more the throttle is closed the harder it is to get good BSFC figures. For this test any brake specific fuel consumption figure under 0.55 lbs/hp/hour can be considered very good. Our WC Holley-equipped motor delivered 0.53. At full throttle the Brake Specific Fuel Consumption was consistently in the 0.39 to 0.44 range. In plain English this motor was proving very fuel-efficient. Now it was the turn of the Demon to show its paces.

First the Demon required a different fuel fitting setup to the Holley, so be prepared for that eventuality. Once on the motor the fuel level was checked at the very effective site plug. At this point the idle was set. With the idle screws barely over half a turn out the motor idled at a smooth 650 rpm while pulling a healthy 14-15-inch vacuum. From here on the same diligent calibration procedure was carried out on the Demon carb.

Although we were supplied with air correctors for both the idle and main jet circuits they proved unnecessary. The fuel curve, like on the Holley before, was about as good as it gets. This left us only with the main jets to deal with. Also since we had now amassed a considerable amount of time jetting with the Holley carb we knew pretty well where things should be. In a relatively short time the Demon was delivering its best.