The crank used was one of the early 330 Olds forged-steel cranks. Coveted for their strength, the 330 cranks were quite popular to drop into small-inch engines. Dale spent a bit of time modifying and lightening the crank: "I took 3 pounds out of it. They're pretty hefty to start with. It weighs like 56 pounds, it was 59 when it was stock." Since modifying the SFI-mandated flywheel was out of the question per EMC rules, Dale also had to re-drill the bolt pattern on the rear of the crank from the oddball 330 pattern. After lightening and resculpting the shaft, it was balanced to a set of Eagle ESP Featherweight Chevy-style H-beam rods. "I went with the longest rod that was still within budget at 6.250 inches. Barely attached to the rods by a set of paper-thin 71 gram wristpins are some custom Ross full-round pistons. At the time the pistons were ordered, Ross didn't have the shape of the combustion chambers to go off of, so they were hand-tailored to fit once they showed up. With a small dome and the pistons sitting just out of the hole, it wasn't hard to come up with 10.4:1 compression. To prepare the block for those pistons, Dale made a custom hot-hone torque plate, allowing 125-degree water to pass-through the engine as it was being finish honed. That brought the engine to an honest 316 cubic inches. After the short-block was assembled, they took a torque wrench to it and were pleased that it only took a mere 7 lb-ft to turn it over.
At a passing glance, the casual observer more than likely wouldn't notice the size of the lifters in an engine, but when it is torn down next to another GM block, it stands out that the lifters sure look awfully big in this little 307. A little digging revealed that during the '80s, Olds moved into the world of hydraulic roller cams and used a big .921-inch diameter roller lifter. This made it legal to use lifters big enough to make Mopar guys jealous, even if they did have to use flat tappets per the rules. Further block details evolved as the Robinsons drilled small holes in the lifter valley to allow oil to fall directly on the flat-tappet camshaft. Also, raised vent tubes epoxied into the lifter valley keep the crankcase pressure equalized between the upper and lower end of the engine.
The cam that was used to motivate the mondo lifters was a COMP Cams grind using the MM Mopar lobes designed specifically for large-diameter tappets. The advantage here is that the angular relationship between the tappet and the cam lobe allows the cam to whang open and close the valves-technically speaking that is. "Looking back now, I wouldn't have gone that big on the exhaust lobe. I think I over-exhausted it."
With no detail too small,...
With no detail too small, the Robinsons spent a good amount of time making sure that the engine looked as good as it ran. The custom Oldsmobile logos on the sheetmetal valve covers really make the engine pop.
During pre-EMC testing, the...
During pre-EMC testing, the dyno guys weren't familiar with tuning the Edelbrock carb, but as Dale has one on his 11-second bracket car, he was able to do some magic to the rods and get the fuel curve where he wanted it.
Hooker supplied the headers...
Hooker supplied the headers for the project. They worked just fine, but there was a little to do at University of Northwestern Ohio when they realized that they had 2 1/2-inch mufflers where everyone else was running 3 1/2-inch mufflers.
The budget-oriented MSD StreetFire...
The budget-oriented MSD StreetFire Ignition system used on the Olds has proven its strength and reliability on the street and at the track. It was good to see it perform flawlessly at the Challenge among a sea of higher-end ignition systems.
The family resemblance is...
The family resemblance is pretty clear as brothers Dale and Glenn pose with their engine. With a working man's budget, the Robinsons get the bang-for-the-buck award. Clearly, the amount of time spent dwarfed the cubic dollars required for such a build.
An HVH Super Sucker carb spacer...
An HVH Super Sucker carb spacer proved a perfect match to the Edelbrock 800 AVS carb. The vacuum-secondary style carb worked out perfectly for the rpm range of the competition, as it was able to warm up and idle on just the primaries, while the secondaries would flap open right at the beginning of the full-load dyno pull.