ItBites,
I used the three quart size because it can hold the pressure up 50% longer than the two quart size. There are some long sweeping turns at places like Sebring and Daytona...
The valve & pressure switch combo on mine measures just under 5" from the face of the Accusump to where the nipple starts joining it to the rest of the plumbing, which is a simple line to the pressure gauge outlet on the BBF just above where the mechanical fuel pump used to go.
bobcowan,
I don't know how old the valve was that failed for you, but mine also failed - at least it leaked through the body a significant amount. The fix was the new-style valve from Canton - apparently they originally used valves from espresso machines
I don't recall whether they had me send in the old one and replaced it without extra charge - at least that's what I think happened.
Tom