I've heard of people doing this to let water escape and prevent rust from the inside out. Is this really necessary? If so where do you guys tend to do this and how big do you drill it? Being in Ohio I want to prevent this pristine frame from rust!

 

I recall rust being a problem with the early front subframes because of poor welding on the join between the upper and lower sections (arrowed).



A.f.a.i.k. this was quickly resolved by Jaguar which should make drilling any drain holes unnecessary.

The subframe on my 1989 XJ40 looked almost 'as new' when removed from the car in July 1999. By that time I'd replaced rusted bonnet, boot and sunroof panel so rust was certainly an issue for me with this car!

Graham