Top quality, made in the UK especially for Lambretta upgrades from scratch.
 
This is a specially made  base gasket  with the correct stud spacings for the 125/150/175cc block Lambretta engine casing.
These have been checked to make sure they are correct.  Big surface area around ports for porting.  Essential you get the correct base and head gaskets fpr setting correct port timings and squish height.
 
These are specificall for use with larger con-rods, JAP conversion crank etc.