[Bit about Andy and Doug snipped, ouch!!]
>This got me curious enough to take out the tape measure. I measured
>four mufflers, which were 20", 21", and two of them at 21.75". One of
>the 21.75" mufflers is new enough to still have a "Walker" label on it.
>It came from TRF I believe. The 21" unit is interesting in that it has a
>"plugged" hole facing rearwards on the opposite end from the tail pipe.
>It appears as though this same muffler might be used for another 2 pipe
>application (1 pipe on each end).
I believe this is standard on UK Spits MkIV and 1500's, don't know why but it
looks weird. I never bothered with a standard UK back box as I thought it
sounded crap, so I bought a semi sport (Narrower Transverse box with 2 pipes
instead of one) from the TSSC, I thought it would be reasonably quite, how
wrong could I have been, but, it's was 80 quid, made of stainlesss and has a
lifetime guarantee, AND was 10 quid cheaper than a Standard one in Stainless!