Nah, it's strong enough. I've used a bunch of adapters over the years on everything from Olds to Ford. Chevy to Studebaker, and some starter relocating ones, and they are all about the same thickness. The light weight is what throws us off, just seems so whimpy.
I love old parts like adapters. A few years ago I bought a starter switchover adapter for an Olds, but never could find the oil filter block off plate that you need to make it work. I saw one at a swap meet, and he wanted like $ 200 for it. One night I was flipping through ebay and found a guy who listed two of them, and he put them under some goofy heading, so I got both of them for $12.00 each. Now I am set for both Olds engines I have in the shop.
Sometime in the '70's a speedshop that had been in business for like 30 years was moving, and had a garage sale. I was one of the few people interested in old hot rod stuff, like intakes and adapters. Most of the other customers were buying stuff for big block Chevys, etc, and I was grabbing really old, dusty stuff, and because no one wanted it, most of it went cheap. I literally loaded my trunk and back seat with stuff. Of course, I caught h*** from my wife when I got home, but you gotta grab a deal when it presents itself.
Don