I've got an Toyota landcruiser that's totaly LPG, no petrol, and no diesel (peopleplease remember it doesn't have Petrol or diesel connected).

When the car starts up, white smoke comes out of the exhaust pipe on cold mornings, and then after running for 5 minutes or so, it goes away.

I've been warned about head gasket, is that a problem? or is it another. I've just bougt the head gasket replacements just in case?

I'm suprised you can get it to start at all, just on LPG. Most LPG I have dealt with requires you to start it on petrol, then switch over when warm, it could just be water vapour burning off when the engine is cold. Check water levels/ oil level, just to rule out a head gasket problem, over the next few days. Why don't you have a petrol swithch over option???

Kingo

unfortunately there is no option of having petrol added, as there's no petrol tank and no pipework for petrol on the car.

i've bought some new spark plugs, i've got all the gaskets and bits and i've bought all the oils and coolants.
i'll buy a think to check compression in a few days too, so i'll have a look at the compression too.