Fast
Road Head
The
Fast Road head is fully reworked before the guides, seat inserts and bulleted
bronze guides are fitted. The inlet and exhaust ports are modified to enhance
air flow without increasing the port sizes to any great extent. This keeps the
port velocities high and aids the production of low rpm torque. The inlet valves
are 1.625" and the exhaust valves are 1.343".
Bhp is increased from idle to a maximum at 5200 rpm with a standard camshaft.
There is a gain of approximately 25% at 3000 rpm and a maximum increase of approximately
30% at 5200 rpm (with a standard camshaft and K&N filters).
This specification of head works well with a standard camshaft and shows even
more impressive gains with a Piper HR270 or Piper HR285 camshaft....( mild road
and fast road type cams ).
While the head works extremely well with the standard twin SU's it will show
worthwhile gains with twin 1 3/4" SU's, I would recommend the fast road
HR285 type cam to compliment the increase in carburetion.
Fast
Road Head