7 The metering blocks from...
7 The metering blocks from BLP have jets in all of the fuel circuits, so making adjustments to the fuel curve is quick and easy. The 5120 series metering blocks wasn't a simple bolt on since these blocks are substantially thicker than a Holley metering block. The additional thickness meant we needed to make custom levers for the accelerator pumps. We also needed to acquire longer fuel bowl screws from BLP. The BLP metering blocks also required that we alter the air bleed sizes and locations. The outside air bleed now feeds the intermediate circuit, while the middle one feeds the idle circuit.
The installation of the 5120 series metering blocks onto our Dominator wasn't a simple bolt on since these blocks are substantially thicker than a Holley metering block. The additional thickness meant we needed to bend up some custom levers for the accelerator pumps. We also needed to acquire longer fuel bowl screws from BLP as well as a selection of jets and air bleeds. The BLP jets and air bleeds have a more streamlined shape than their Holley equivalents and they are available in a wider selection of sizes.
Dry-sumps are very popular for circle track racing and are used in almost all of the professional-level drag racing classes, but they haven't caught on with the average Mopar bracket racer for a variety of reasons. One stumbling block we discovered in converting a big-block Mopar engine over to dry-sump is the lack of parts. We could not find vendors for either a block plate, or a dry-sump drive, so we had to design our own.
8 Since the BLP metering...
8 Since the BLP metering blocks are thicker than the standard Holley blocks, we also had to bend the lever arms for the accelerator pumps. We have gotten word, though, that Mike at BLP is looking into it.
We decided to go as low buck as possible. A custom-built dry-sump pan wasn't in the budget so we decided to see how well our existing deep-sump dyno pan would work as a dry-sump pan. Our existing pan was already plumbed for a dual-line swivel pickup so that gave us two pickup points where the scavenge lines could be attached. The existing pickup in our pan was designed for wet-sump operation, but we didn't see any reason why it wouldn't work as a dry-sump pickup so we decided to give it a try.
Given that our existing pan only had two lines coming out of it, we were restricted to running a three-stage oil pump consisting of two scavenge sections and one pressure section. Since this was just a test, we borrowed an older three-stage dry-sump pump from a local circle track racer and fabricated a simple mount to hold it in place for the dyno session.
9 We purchased a spline drive...
9 We purchased a spline drive assembly for the dry-sump oil pump from Peterson Fluid Systems. The crank trigger assembly came from Mancini Racing.
The engine bolted right onto the dyno, and once the lines were hooked up, we were able to quickly prime the oil system by spinning the pump with a hand drill. Our first round of testing was with the Super Victor intake and 1.70 rocker arms on both the intake and exhaust. The engine sounded great during these pulls, and it made an average of 780 horsepower at 6,600 rpm throughout several pulls. After a quick swap to the 1.85 rocker arms, we made another handful of pulls and saw a consistent set of 790 horsepower at 6,600 rpm readings for a solid 10 horsepower gain. We carefully inspected the rocker arms and pushrods after the dyno tests, and everything was in great shape, which told us that our new pushrod oiling setup was working perfectly.
The jetting recommendation that BLP had provided us was very close right out of the box. We made some jetting adjustments to the intermediate circuit, but the main jets were fine. One nice feature of working with these BLP metering blocks is that you can quickly adjust the specific circuit that needs attention. The new ignition system from MSD worked perfectly during these dyno tests. With this much ignition capacity on hand, we can start to open up the plug gaps in a search for even more power gains.