Although not of course directly comparable you may find the Jensen Owner's Club useful where a number of these conversions have been carried out.
518gearbox
Steve Payne is very adroit at the conversion and generous with his advice on this searchable open Forum
The Jensen Owners' Club • Index page
My CV8 has had this work done which involved cutting out a cross member and remaking it to fit the 518 gearbox.
The conversion has improved the car considerably. Be sure also to get a torque lock-up device included in the gearbox.