I agree with bm an lpg kit would be easier to do and just about half your running costs,but you allready have the engine so maybe doable I've enquired about lpg for my scimitar to improve the 19 mpg

about £600,DIY fitted £1000 ish for garage.If you measure up you may find that the engine will fit without too much cutting about just a case of mounting points,the problem will be with mating to the gear box or what box to use. JLH on the otherside,Oh dearI'll be banned from here now

Could probably give you more advice than anyone else. I'm a bit worried about LPG, round here it's steadily increasing used to be about 60p a litre now 90 and the gov being the highwaymen that they are will soon cotton on and start whacking tax on it as soon as they see more usuage,so could become a wasted exercise.