Originally Posted by DaveW
Those triangular panels are a weakness..

Actually, they are chassis savers. At the request of Bill Fink, an American dealer, the MMC began installing them in overseas cars in 1978 and they soon became standard. They are called gussets. They move the stress point, in this case from the bulkhead forward. Before they were used, the flexing trad chassis would commonly crack at the bulkhead, requiring a body-off job for a chassis repair. Actually, the best way to repair a chassis is to replace it, however, this gusset offers an alternative on cars that have them.

Sadly, not fully understanding the gusset, the MMC used a length that also, for quite some time, ended in the front where they had holed the chassis for an exhaust exit..whether an exhaust used it or not. That became the new site for the later cracks. But I HAVE seen people repair cracks there and they can last. That means a 20k saving. Of course, like the change of the wing brace, the MMC spent decades trying to figure out a cure for the new crack point.
https://www.gomog.com/allmorgan/ChassisGussets.html#STRENGTHENING

I do not suggest you remove the gussets.

L.