The 'tulip' shape we see in our standard Triumph valves, and most other
production valves, has been in use and developed since poppet valves were
invented. It provides a smooth flow through the valve under maximum flow
conditions.
The "penny-on-a-stick" profile is a development of that, and does allow
better flow when the valve is partly open, so improving overall flow
especially under severe operation conditions, high revs and when the valve
seat has been purposely made shallow.
But few Triumph drivers will use their car in this way, and will not benefit
from such mods. Moreover, the combustion chamber shape suffers from the
valves being close to the wall, which inhibits flow, so that valve modifying
can have only a limited benefit.
Go for it if you like experimenting, but a lot of other mods may be needed
to see a benefit, if any.
John
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