Last month, the engine machining, blueprinting, balancing, and assembly was completed. Her
In the first installment, we put the finishing touches on our Barton RB wedge. We featured some of the balancing, blueprinting, and machining procedures a motor needs. Barton builds all types of motors for all kinds of customers, be it a restoration, a street/strip, a small-block, a big-block, or a Hemi.
Many, but not all, motors completed at Barton's go for dyno testing. Ray gave us the OK to prepare our motor for the dyno, so we installed the distributor, ignition wires, plugs, carburetor, and the oil and filter. Next, the wedge was loaded onto the dyno stand and wheeled into the dyno room for hookup to the water brake.
Before dyno testing our motor, Ray mentioned his new DTS dyno is dead-on accurate, but the horsepower readings would be 5 percent lower. For example, a 600hp motor on his new dyno would have shown 630 hp on his old dyno. Here's a brief summary of our RBRE 493: mildly ported Edelbrock heads, 10.8:1 compression, 638-lift solid cam, MP M1 single-plane intake, and Holley 950 HP carburetor.
Precautionary measures were taken before the motor was rung out on the dyno. Our motor was warmed up and run at 2,000 to 2,500 rpm for 30 minutes. This ensures proper cam and lifter break-in. Dave Barton handled dyno duties for the day. After cam break-in, we removed each valvespring and returned the inner springs to their home. The valve lash was set, and we were almost ready to rock!
First, Dave made a 5,000 to 5,500-rpm pull and then three 6,000-rpm pulls before letting it rip. Initial testing showed our combo made its most power at 39 degrees total timing. We were comfortable the air/fuel mixture and oil pressure was on, so Dave cranked it up to 7,000 rpm. The dyno's readout told us 615 hp at 6,400 rpm and 596 lb-ft of torque at 3,900 rpm. That's big-time power for any street-driven machine. We made another baseline pull, and our stroker put out identical numbers. With a solid baseline, we were now ready to try a few bolt-ons.
The smaller tti headers with 1 7⁄8 tubes and 3-inch collectors improved the peak tor
A good friend offered his brand-new, still-in-the-box 1,000-cfm Race Demon carb. Off came the 950 Holley HP, and on went the 1,000 Demon. Two consecutive pulls showed us 5 more horsepower and 2 lb-ft of torque at the same rpm. Our deep-breathing 493 enjoyed a bigger carb. So far, we were on the road to more power. Since they've worked well in drag testing, we tried a Wilson Manifolds carb spacer next. This 1-inch, four-hole, tapered spacer was worth a tenth on both a 360 Challenger and 440 R/T. Once in place, we were astounded when peak horsepower jumped up to 633 at 6,400 rpm, for an increase of 13 hp. This spacer was designed for the single-plane intake, but it worked well on the dual-plane RPM in those previous strip tests.
We felt the dyno headers, with their 2 1⁄4 into 4-inch collectors, were too large for the intended power band of our street motor, which is 3,500 to 6,000 rpm. We had a hunch the smaller tti headers, with 1 7⁄8 tubes into 3-inch collectors, would be more beneficial. The headers are about 12 inches longer and broaden the power range. Since the '60s, 1 7⁄8-inch tubes have been the ideal size headers for a street/strip 440. Would they be the right size headers for our 600-plus-horsepower 493ci motor? On the first dyno pull, the tti street tubes proved to be worth 32 more lb-ft of torque at peak rpm. At 4,700 rpm, they showed us 51 more lb-ft of torque. The smaller tubes lost only 2 hp-631 at 5,900 rpm-but peak horsepower was 500 rpm less. The 3,500-6,000-rpm average horsepower and torque went up 29 and 31 respectively, more than we expected and great for better street driving.
In previous strip testing using 1-inch carb spacers (open, four-hole, and four-hole tapere
The cam swap (solid flat tappet to solid roller) made it necessary to use pushrods that we
We installed the Comp Cams .575-lift Magnum solid street roller straight up before install