SU carb piston lifts.

["Janice/Matt Matthews" <matthews-home@worldnet.att.net>]

I would appreciate some help from the Spitfire racers.

We have a SCCA FP 1300 Spitfire with dual 1.5 inch SU's.

Under load at 5000 RPM, our carburetor pistons only rise about 0.5 inches
instead of much higher. If we put the carbs on a flow bench so that the
flow is equal to the volumetric demand of the 1300 engine at 8000 RPM we
get similar elevations.

What carburetor piston elevations do other Spitfires get? Or other Triumphs
for that matter.