Don't know about R1 engines in a Caterham but, I'm looking to buy a Hayabusa engine in a Caterham. Some pieces had to be custom built but in the end no trimming to the car was needed.
The hayabusa engine/tranny being much lighter than a regular car, this particular SV body caterham weighs only 1070lbs. With the 185hp of the Busa engine it gives the car the same hp/ton ratio as a R400!!! I haven't driven it yet but it is very quick! The builder tested it on a track and did the 0-60mph in 3.25sec!
Can't wait to test drive it! 😬