Exhaust pipe length

[steve.thomas]

Hi,
Can anyone advise if the tailpipe needs to extend beyond the rear bumper, and if so by how much?

The car is a '72 S130 with the longitudinal type silencer, and the exhaust itself is an aftermarket stainless steel item which looks to be in perfect condition but i have no idea of its age. The tailpipe finishes flush with the outer edge of the rear bumper. The reason for the question is that the car is fairly noisy and there does seem to be a smell of fumes in the car, but that may well just be the petrol fumes from the breather pipes or the several holes in the bulkhead that I haven't plugged yet.....

Thanks in advance for any help.
Steve