Rocking Horse springs to mind.. 
hmmm.
and a gas kit is gonna be ££££'s 
its a toss up between an MV6 and a Granada 24v..
A UK gas conversion is circa £1300 apparently but less than half in Poland.
Converted MV6's are out there but need a good looking for.....
And far better than a Granny, even a 2.9 Cosworth 
As an ex Granny 24v owner, if you are after a frogeye ugly 24v, proceed with great caution, cam chains become noisy, there is an updated tensioner with a different sized oil port in it for better self adjusting... BUT, once chain damage is done, noisy... if it's had a recent oil change, this maybe silencing it.... apart from that... Get a Meega, you know you want to....
Hope this helps...
DC 
Used many a Cosworth 24v in my line of work as Company Cars. Once you got used to the boat like hadling (similar to the 'Meega) it could hustle along quite nicely as long as you set them up correctly for the bends. Don't brake off too much speed at any one time though, as it took a day or two to restore progress......

Had an appetite for rear tyres, especially on the inner edges with a full boot of kit, but I liked them, on the whole, especially the hatchbacks. Biggest let down was engine noise (tappets/adjusters) which sounded like a skeleton dancing on an empty biscuit tin at times......