I'm looking at putting a new 1 litre ecoboost engine into a kit car, but the car is designed to be rear wheel drive. I've never attempted this before and wondered if anyone here had? Or could point me in the right direction for more information or a conversion kit?

As you know the engine is normally mounted FWD, transversely, the engine was fitted in a formula ford chassis, which was RWD, if you found out how they did this, and what gearbox etc they used, you could probably do the same or similar

http://www.autocar.co.uk/car-review/ford/first-drives/formula-ford-ecoboost-first-drive-review

Edit - it says its mid engine, longditudinal (not transverse) RWD, with a 6-speed sequential gearbox (i wonder if it was motorbike based)

with 200Hp (from the 1L, 3-cylinder!) and 500kgs, it must really shift!

...I'm looking at putting a new 1 litre ecoboost engine into a kit car, but the car is designed to be rear wheel drive.

That's not much information, but I'll assume that you are intending something in the Lotus-7-U-like/Caterfield universe...entirely different answers are not only possible, but more appropriate for other vehicle architectures.

Edit - it says its mid engine, longditudinal (not transverse) RWD, with a 6-speed sequential gearbox (i wonder if it was motorbike based)

If my guess of the configuration is correct, that gearbox won't help. That's something like a Hewland, although with the clusters orientated at 90 degrees to the common Hewland one.

That doesn't look to be motorcycle based, and the OP probably wants a reverse gear...now that isn't necessarily a show stopper as you can buy a reversing box to add just a reverse gear, but the things aren't cheap (what is, in motorsports?) and adds weight (which may not be a big consideration for the OP, but, again, in motorsport can be a show stopper).

I've never attempted this before and wondered if anyone here had? Or could point me in the right direction for more information or a conversion kit?

What you really want for a 7-type vehicle is a Ford type 9 gearbox and the appropriate conversion bellhousing. Now, I don't actually know of anyone who does an ecoboost-to-type-9 bellhousing, the last time I looked it being rather before the ecoboost became popular; however, Burton Power do them for a variety of Ford engines, so I'd be surprised if they, or someone like them, didn't have something by now.

(The reason that you want a type 9 (or an improved-type-9-copy), as opposed to all of the other gearboxes out there, is that there is the widest range of bits for the type 9; you can go sequential (you won't like the price, but you can do it), add an extra gear, have a choice of ratios, have a choice of dog vs synchro, and you can get a variety of upgrade parts only limited by your ability to keep opening your wallet. You can also get from, eg, Quaife, Tran-X and others, their own design of gearbox specially designed to fit into the same slot and stronger and/or lighter - unless there is some horrible reason that a type 9 won't fit, the type 9 really is the first thing that you should consider - you can also get them from scrapping Sierras, and re-con them yourself with appropriate upgrade parts, if there are still any Sierras being scrapped).

Quaife - mentioned earlier - have dropped out of selling the 'upgrade-a-type-9' parts themselves, and now only sell their own designs directly, and you have to go to, eg, Burton Power or other agents (perhaps Demon Tweaks?) to get their 'upgrade someone else's 'box' parts.

And, you need to think about the sump (which might not sound like the most interesting topic in the world, but bear with me). If you are able to and are prepared for the expense of dry sumping the engine, you can fit the engine a little lower, which will lower the c-of-g. If you aren't, the existing sump will have to be examined to see if it fits in with your installation plans; if it doesn't, you'll still need a new, custom, sump and while that won't be as expensive as the full dry sump kit, it won't bring you the advantages of the dry sump kit, either.