[unruhjonny]

This is an interesting discussion.

Incase I missed it, does anyone have numbers on the "69-78" cast rods to compare against the other castings being discussed?

I believe this was the first mention of them in this thread:

Originally Posted by tom s

For a street only engine up too 4in stroke I would run a set of 69-70 cast rods before any of the 58-62 forged rods.JMHO,Tom

I had understood that the cast rods were good, but this prompted me to look at my McCarthy and other Pontiac books I had here, and I couldn't find a single mention of how the 69-78 rod held up against the others.

[tom s]

My experience with cast rods.Some years ago I was in AZ driving my then 63 Tempest convert on the freeway and all of a sudden the engine shook and stopped.Got the car back home,pulled the heads off and found one dropped a valve.The head of the valves went Xways through the head of the piston.Pulled it apart and found with all the damage the rod was still attached to the piston and the crank.With further inspection I found the rod had twisted a touch BUT held together that caused me when building a street 421 for my 62 GP to trust a set of rebuilt cast rods that came with the engine when I bought it in pieces.This engine has been in the 62 for some time with many diff intakes.It has the repo Bathtub mule from when we made them.The engine sees off idle to max of 3000 and never misses a beat.I have posted pics of the rod-piston assm a couple times on this site and if anyone wants a look,PM me with a cell number and you will have one.FWIW,Tom