21A rods set up on a 4" Merc crank

[petehoovie]

Originally Posted by Bored&Stroked

Also, if you can have the rods "shot peened" . . . that is a good process to stress-relieve and add some strength. You'll need to balance BOTH ends of the rods and make sure that you do NOT grind the strengthening rib off of the rod-cap.

You need to make a fixture for your lathe to cut the side-area of the rod caps to set the big-end weight. Ford NEVER ground the rib on the bottom and these rods do not have balance pads like modern rods.

Couple pics on my setup:


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Here is what most shops will do . . . they grind the bottom cap rib! They don't know any better and weaken the cap:
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Video on bearing sizing:

https://www.youtube.com/watch?v=CyVLsPdbhS8

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