might come and see you don after its up and running, those bbq burner style mixers were what caused the problem with the backfiring, have inserted vk efi commodore venturis into the air stieam using the burner rings as housings.

The only problem with the su lpg set ups is getting enough draw on start up but with the mixer im using it has a bit of pressure in there that helps push the gas out into tthe air stream. This is as the su set up on start up doenst have as much draw for the gas as a conventinal single inlet set up.

the plungers are pretty much redundant with lpg As i inderstand as the butterfly at the back of the su does most of the metering in the inlet side of things and may insert helper spirngs to keep the plungers raised a bit so they done block off air flow completely, but once again this will affect draw of the gas.

As you would understand, its all a matter of seeing what works with this kind of set up to get it running, no off the shelf kits really available.

Its on an a15 with mild cam so may not be as bad as the L18 melt down, but atleast it may warrant a L series conversion if it all goes wrong (hope not)