The use of a Milodon oil filter...
The use of a Milodon oil filter adapter is standard operating procedure in the big-block Mopar world. Instead of pulling oil through the little 3/8-inch hole in the engine block it pulls oil directly from the sump in the pan, bypassing some narrow, sharp bends that rob oil pressure.
Once the parts were back from powdercoat, Robinson continued the port work from the cylinder heads all the way up the intake runners where it terminated in the plenum. They tried several versions of spacers on top of the intake but stuck with a basic half-inch phenolic open spacer from Holley. Running a tunnel ram definitely changes how the engine pulls fuel, and the jetting can be quite different. "The first couple of tests we did with the tunnel ram we didn't have enough jet in it and we pushed a head gasket once." A quick swap of a head gasket and fattening up the jets set everything back in order.
Holley was their choice for carburetors. Dual 1,000-cfm HP Series carbs were sourced and given the SKMFX treatment. They used annular boosters to get better fuel atomization down at the low end of the rpm range and it still kept from creating any restriction up top. Robinson felt quite comfortable tuning the carbs: "That's really all I've ever done. I really haven't messed with fuel injection a whole lot. The bulk of my experience is with carburetors. I was really hoping to show up with two Thermoquads to be honest. Just for fun. I've had fantastic success with the Thermoquads but it probably wouldn't have worked as well as the Holleys."
Some ignore the ancillary components but Robinson made sure his engine was loaded for bear. A Moroso electric water pump was installed that has been proven to free up 20 horses and with the CNC-machined billet impeller; it moves up to 21 percent more water than comparable pumps while only drawing 7 amps. Even under the stress of three back-to-back pulls after warming up, the engine never climbed over 163 degrees.
Ignition was rock solid thanks to the engineers at MSD. Using a 7AL2 ignition box and a Pro Billet distributor, the SKMFX team was able to monitor and dial-in the engine easily. "It had always made best power at what I thought was 36 degrees on the dyno, so when we put the last camshaft in it, we started testing at 32, and power was excellent. Whenever we bumped it up to 36, we'd lose power and it had never done that before. It was actually during the photo shoot that I happened to rest my hand on the damper on the end of the crank and I thought the whole front of the crank moved forward like the thrust was out of it, but it wasn't. The damper had failed and the outer ring had moved forward like a quarter inch. What had happened was at the contest, on the dyno during the tune up period, I had elected to put two more degrees in and I think we must have already been at 36 or 38 degrees in, and we must have run with about 40 or 42 degrees." The added timing showed as it rattled pretty hard down low but she was tough and held up.
Shell V-Power 91 octane pump gas smelled as good as napalm in the morning as it burned and passed through the Hooker 2-inch headers. Its final destination lay just past the MagnaFlow mufflers and into the cool afternoon air of America's heartland.
Locked and loaded, the Commando in black sounded as deadly as a Barrett 50 cal while stuffing 690 horses down the throat of the DTS dyno. It put up a mighty battle and the boys were pleased by the valiant effort. "That power range is a little more than what I'm used to building. The bulk of our stuff is circle track small Chevy stuff, so to build a big-block in the 700hp range it was a little different experience. Because Engine Masters requires you to run on pump gas, what I've been learning and going back to is that all of our circle track classes are pretty much required to run on pump gas now. So I can take what I've learned from applying it to the Challenge engine and offer it to my customers in their engines." Whether it is a circle track, drag, or street engine, SKMFX is clearly ready to do battle again. One thing is for sure though, the next time they enter the EMZ (Engine Masters Zone) they won't take any prisoners.