C3: distributor shielding spot welded vs. rivets

[Dan Pepper]

When did GM start using the 2-piece riveted unit as opposed to the spot welded unit?

[Terry M.]

Re: C3: distributor shielding spot welded vs. rive

There is also a two piece screwed together unit.

[Dan Pepper]

Re: C3: Dates for change?

Reason I'm asking is that I have two different distributor shielding boxes - one of which I'd like to mount on my Oct. built '69 coupe. One unit is spot welded, the other is riveted. Terry, are you saying there is a 3rd design too? Regardless, when were each of these different designs introduced on the line?

[Terry M.]

Re: C3: Dates for change?

Yes, there is a third alternative. The two halves of the distributor shield are held together with two small, black round (well maybe oval, I would have to look to be sure) cross recess screws on the passenger side. My early 1970 small block has that feature.
Since no one else has answered, I am willing to go out on a limb, but before I go too far out allow me to ask if you know what the latest edition (purple cover) 1968-69 TIM&JG says about this? And no I haven't looked yet myself, I was really hoping someone with a reasonably original car would come forward so that we could double check the manual.