The engine fired right up with a very healthy sound as soon as we hit the ignition switch. At a 2,000-rpm fast idle, the engine had a steady 15 inches of vacuum, but the vacuum number dropped sharply once the idle dropped much below 1,500 rpm. Of course, with a solid roller camshaft it isn't a good idea to allow the engine to idle much below 1,500 rpm, since the lifters need plenty of splash lubrication to keep them operating smoothly.
Once the engine had warmed up and everything passed a final inspection, we pulled the lever and watched the needle swing around the dial. With the standard port-window heads on 505 inches, we knew the torque number would be good, but we were still a little surprised to see 637 lb/ft at 4,000 rpm on one of the first pulls. The best torque reading we saw during the dyno pulls was 643 lb/ft at 5,100 rpm, but many of the pulls were in the 620 range. Peak horsepower readings were right around 680 at 6,000 rpm depending on the dyno pull. The very best number we saw was 683 at 6,200 rpm when using a Wilson spacer under the carb. Several other runs hit 680 or 681 at speeds between 5,800 to 6,100 rpm. It isn't uncommon to see the peak numbers vary a little during testing since there are so many variables involved. We tried several different carb spacers and played with a couple of different carbs during our test session, but nothing seemed to change the numbers much from the 640 lb/ft of torque and 680 hp levels. All in all, we were very pleased with the power that this combination made on the dyno-680 hp in a 3,400-pound car would give a 5:1 weight to power ratio which is enough power to run 10 flat quarter-mile times at 138 mph.
Wrap Up
This was one of those test sessions where we answered some questions and raised a few new ones. We certainly demonstrated that the street roller camshafts from Comp can make a lot of power without breaking the budget. In hindsight, we probably could have gone one size smaller on the cam and had a little more vacuum at idle without giving up much top end power. So if you're thinking of running a Comp street roller in your 500-inch daily driver, you might want to go a bit smaller than our choice. The nice thing about using a roller camshaft is that if your first choice wasn't perfect, you can quickly slide in a different camshaft profile and you do not need to buy new lifters.
We also learned during this series of tests that the new Super Victor intake is a very nice intake that was easily capable of making our power goals. We did not have a Victor 440 intake on hand to do a comparison test with, which in hindsight might have been interesting. We are now wondering what the power difference would have been between the smaller plenum Victor 440 intake and the large plenum Super Victor.
But this is the way it often goes with dyno testing. We usually learn a lot of interesting things, but we also often come away with some other items to ponder. Good thing there's a new issue of Mopar Muscle every month! That gives us the opportunity to keep trying new things and to tell you what we learn.
Mopar Performance has had an M1 intake manifold in their catalog for a number of years that has standard sized ports and a Dominator flange. PN P4529725 is the version that fits RB motors while PN P4529724 fits the smaller B motors. We thought it might be interesting to try the 725 intake on this motor while we had it on the dyno just to see how the older Mopar design stacks up against the new Super Victor.