The connecting rods are key to ease of assembly. I chose the Eagle "SIR" rods for a few reasons. Stock rods need to be resized, and require ARP rod bolts, balancing, bushings for full-floater pistons, plus grinding on the bottom of the cylinder bores to clear the rods and rod bolts. So, for about the same money you'll spend upgrading the stock rods for the job, the Eagle SIR rods are an excellent alternative. The SIR rods have all the requirements for this application, are chamfered for the sides of the journals, and do not require any grinding on the block for clearance. I was amazed that we didn't have to grind anywhere to make this crank fit with these rods. In my opinion, go for the Eagle SIR rods unless you're building a rod-breaker of an engine.
I had no plans to push this motor that hard, so the Eagle SIR was enough connecting rod to handle the horsepower-basically a wash with regards to the cost over up-fitting the stock rods, and it relieved us of the task of clearance-grinding the block. That was almost as neat as investigating a classified ad for a '69 Plymouth for $500 and finding that the valve covers have spark plug holes through them! OK, not really that neat, but what a cool surprise after we had all the cutting tools ready. In fact, Randy grabbed an Eagle H beam and found that we still would have to grind about as much to fit the stock rods to the block as we would the Eagle H-beam rod.
I used Clevite bearings that have been chamfered on the sides to clear the radiused fillets on the sides of the crankshaft journal. DO NOT attempt to use unchamfered bearings with this crankshaft, as it will be somewhat tight when you assemble it, and it will ruin the crank if you try to run it that way. During assembly, the connecting rod bearings require careful orientation. It's always a good idea to spin the crankshaft after you install every piston to verify you installed it correctly.
In sum, the guys at Diamond Racing put together a wonderful package. All the tolerances were perfect, and this stroker went together as easily as any nonstroker version. If you install an MP windage tray, there is some manipulating required to clearance the inside of the windage tray. The only upgrade I made for the installation of this engine was adding 36-pound injectors to handle the extra cubes. I installed a completely stock throttle-body to display what could be gained from only a short block. I also used the stock oil pan from the 318 with no problems.
Finally, don't forget to order yourself another Woodruff key for the crankshaft. The crankshaft is drilled for a pilot bearing, so stick-shift guys will need to get a new pilot bearing.
The ResultsOnce preparations were made to fire up this beast, we hit the key and immediately noticed the difference. When I put it in reverse, the torque at idle pulled the truck out of the garage. The 318 could not have handled that on its best day.
After the break-in process was complete, I put a G-Tech in the cab and ran severely traction-limited mid-12s. Then it was time to head to the track. I made two terrible launches in Second, missing Third gear in both passes, yet still netting a decent 12.84 and 12.89 at 113 mph. I attempted to leave in First gear on the third pass, and that proved costly. I tore the pinion support from the carrier and bent the driveshaft. The 408 and 4.01 First gear ratio produces a lot more torque than the stock Ford 9-inch carrier can take. This is with the mildly worked 318 heads.
So, I pulled the engine and dropped it into a friend's Dakota, which was equipped with an automatic, and we bolted up a 650 Demon double-pumper carb. This is a '97 Dakota, which weighs about 500 pounds more than mine. The truck boasts a mild converter, a 3.91 rear gear, and sees street/strip action. The result was an impressive 12.17 e.t. with tire spin (a 1.84 60-foot time), and a top-end charge of 115 mph.