[6pack] Connecting Rods with Relief Holes

[Brian J. Alwin]

I found a donor engine for my "hot rod" TR-6 engine project. It's a late
72/early 73 that's likely been apart once before. It's in fine condition
inside though and even appears to have a forged crankshaft.

My question is that the connecting rods on 4,5,6 have relief holes at the
base of the beam. Any idea why this was done to certain rods? Are they
structurally inferior to those that do not have the holes?

Thanks!

> Brian J. Alwin
> 1972 TR-6 CC79085
> Rochester, Minnesota