Following earlier posts I went ahead and rebuilt my engine its a 3.5 with twin SU's.
At the same time I changed to cone type filters and BBW needles on Badgers advice on here. Very pleased with the way it now runs on petrol. (Thank you again Badger)
However there has been no performance improvement on lpg. It occurs to me that the needles have provided the extra fuel required when on petrol so maybe some form of adjustment is required to the lpg system to provide the corresponding increase in fuel. Its a basic system manufactured by Landirenso.
Gerald