1963 idler arm markings

[Timothy B.]

I wanted to post and show the markings on this idler arm that came off a complete 1963 power steering unit I purchased for my car. This unit came from a burned 63 and I believe the idler arm to be original.

The J/G states the part # 3779185 for non P/S idler arm. The J/G also states 335GMT3779185B for P/S idler arm. I believe all the idler arms are the same and the J/G to be incorrect. If you look at the end cap on the arm pictured the B stamp is visable.

I wanted to share this because I could never find the B stamping as it was not visable until wire brushing the area.. I can't make out the cast #'s on the top.

[John H.]

Re: 1963 idler arm markings

The J/G states the part # 3779185 for non P/S idler arm. The J/G also states 335GMT3779185B for P/S idler arm. I believe all the idler arms are the same and the J/G to be incorrect.

Tim -

That's correct - the same idler arm was used with and without power steering. Whoever wrote the description in the JG apparently wasn't aware of the variations in forging numbers; the forging process beats hell out of the dies in the forging hammer (press), and there are multiple sets of dies, each with their own number (like the pattern numbers on GM castings, for internal traceability) in addition to the base forging number.