Marcos Maniacs

I need to give a newly purchased 1600 some remedial attention to the 
floor panels if I am to enjoy the short summer we have in UK, prior 
to a major rebuild during winter.
Can anybody tell me where I might find information or photos/diagrams 
of the best way to go about this. I believe that it is not 
recommended to do this from beneath the car, but that the car should 
be turned on it's side???? Can anybody confirm or deny this?

Also to any UK readers......does anybody have experience of fitting a 
UK 2.0l Pinto engine into a 1600?? Best Donor car? (Sierra or 
granada?) as I also want to fit the five speed gearbox
Thanks 
Paul