Flawebmaster

I bought a 390 engine to rebuild and upon dissassembly found that the motor had 5 C7AE-B rods and 3 C6AE-C rods. The sides of the rods are numbered 1-8 and look to be original. Is this possible? Should I buy some rods so that they all match?

kdtrucker

ford has used both of those rods used in either of the 390 or the 428. The rods should be the same length eyelet to eyelet, so it doesn't matter if it has different castings, as long as they have been balanced all the same you'll be fine. If one set is considerably heavyer than the other set then they are beefed up for performance, then you might want a matching set. Your 2U is a 3.78 stroked crank used for the 390 406 427.

Flawebmaster

Actually, the rods look identical except for the casting number. I guess it's OK to use them as is?

FFR428

The rods are identical. Only difference could be in the rod bolts as both were used in big and small rod bolt apps.