Longitudinal reinforcement?, do I trust a PO repair? Options

[ben914]

Greetings to all! I'm new here, just discovered it after having been on the 914 Rennlist mailing list for quite some time.

I have a '74 914 that I'm converting to be an electric car -- bought it without its engine, and I'm trying to bring it back to life. In tearing it apart, I've learned much about the 914 and all the wonderful little places that rust likes to hide. One of the worst, however, was discovering that the most of the right side of the engine compartment wall (where the battery box is) must have rusted out pretty significantly, because someone cut the entire thing out and welded in a patch. Even this is rusting a little bit, which makes me rather unhappy. Interestingly, however, when I removed the rocker panels, the longitudinals appeared to be in great shape, and the car has no body flex that I can see. What concerns me, besides the fact that this patch is somewhat rusty, is the fact that the original structure seemed to be two sheets of metal at slight angles to one another, and I have to wonder whether or not this patch will be strong enough. If I stick 700lbs of batteries in the car, is it going to snap? Or is most of the weight resting on the lower longitudinals?

I'm sorry I can't get really good pictures of it -- it's kind of an awkward area to get at. Since I'm trying to build an electric car more than restore a 914, I'd rather not have to go tearing the body panels off to weld more stuff in there. But do I have to in order to make sure my car won't break?

Thanks in advance,
Ben