>The issue that Mr. Berg is worried about is the ability to
>over-rev and "float" single springs when you install dual carbs.
>"Floating" refers to a condition in which a engine is turning such
>high RPM that the spring tension provided by a single spring is unable
>to completely close and seat the valves in the head. Keep the revs
>reasonable (under 5000 rpm) and you should never experience
>"floating".
>
My Haynes book states that the 1600 dual port engine has a rev limit of 4400
rpm and that 65 mph is the top speed.  Under these conditions you could use
HD singles, but I have NEVER been able to hold to these limits in a bus.
Certainly not on California/west coast roads with a loaded bus.  I float
dual spring valves, or at least have broken them.  Maybe I have a personal
problem? :) I don't think you can sense valve float as readily as Mr.
Carrington believes.

What is the rev limit on a dual spring type IV?

Sincerely,
Eugene
'71