Eagle 4.250 Cast Crank Broken

[RICK LAKE]

Racco I ran eagle rods when they first came out. Reason, I have a set of Leman rods that are still in the box and 40+ years old. They also weight 100 grams more than the eagles. My rods where sized and checked for cracks. Rods bolts where replaced with a better ARP 2000 bolt instead of the 8460 that came with them. My machinist is one of the best in the country told me this, LIMIT your rpm range to 6,200 MAX. Oil pressure is also your friend, 55-60 is ok for street but 70-85 is better for track driving with an FE motor. Run a large oilpan with a min of 7-8 quarts and trap doors to make sure no air gets into the pump. He balanced the whole rotating assembly to "0" with everything on the crank, pulleys, dampener, flywheel with clutch, and weight of pistons, rods, pins, clips, and oil of 3 grams. Every thing was indexed. This was also a torque built motor, not high hp motor. I think that there was a note with the new rods about max rpm of 6,700 rpm also. I am guessing you also didn't do many heat cycles to break in the motor to. IMO a 20 minute break in is only to fine out if the camshaft and lifters are going to fail or last. Min of 10 heat cycles with nothing over 4,000 rpms is a good place to start with a new motor. To each is own. Rick L.