My story with Gas ? It all started about 8 years ago, I had a turbo-diseasel 90, fancied a Discovery, and REALLY fancied a V8. A V8 Disco came up locally, nice condition, good price, bought it.
Set out to convert it, and back then it was REALLY hard to find any information - if I knew then what I know now and all that. I used a kit from Chris Perfect who did various bits for Land Rovers. It was never quite right as the mixers didn't suck enough gas - but it ran well enough.
The economics were that the kit cost me about £680, according to the guides, a V8 was about £1200 cheaper than the same model with 200tdi diesel - so payback was zero days !
The conversion took a while as I insisted on doing things in a way I'd be happy with, so cylinder went under the back and I made a smaller petrol tank - someone else did the seam welding on the stainless I'll hasten to add ! Pics are
here. The mixers in the pics are a different set I tried, they weren't any better.
It originally had a single 50l tank under the back, but I latter added sill tanks to give a more useful range.
I think it was about 5 years ago that a friend bought a V8 Range Rover - and of course the first question to me was "what do I need to gas it ?" I looked around, and worked out that it wouldn't cost much extra to go and do a course over buying a kit - plus we'd get to use someone's workshop (better than outside on the drive !) and get to pick their brains. Three of use went and did the three day course at Autogas Worldwide, which none of us regret in the slightest.
While we were driving to the course, my mate casually asked how much I saved by running on gas. When he tells the story, he says that I went quiet for a couple of minutes (as I did the sums in my head) - then remarked "bl***y hell !" I'd never worked it out before, and was surprised to find that it was about £1500/year vs running on petrol
Next up, we did my mates Series III. Don't laugh, but this was a leaf sprung Land Rover, 2 1/4 petrol engine, and ... rally prepared

We gassed that with a basic open loop setup for not a lot of money - it ran a lot better and was cheaper too. Mind you, we got some odd looks in the service areas with our red cylinders and a hand pump.
About 3 years ago, a friend in the trade asked me if I was interested in a 110 he'd just taken in as a part-ex - 110 Station Wagon (12 seat) with lovely V8 engine. I looked it over, looked at the copious list of faults on the MoT fail sheet, considered the price being asked - and nearly took his hand off. As it happened, I had some time off work and used this as a de-stressing project - it did need a fair bit of work.
Gas conversion is a 66l toroidal under the back where the petrol tank was, 36l cylinder under the drivers sill, and a relocated petrol tank in the rear wing. Up front, a Romano reducer and Leonardo controller.
Apart from these motors, we've also done a couple of conversions for friends - one in an old BMW 318, the other in another Range Rover. Kind of puts you off doing it for a living - the Range Rover owner got a payback in less than 6 months and was still whining about the cost when he sold it three years later
