Nice car Dave. Not a lot of space so numbers could be lmited and priority has to be Jaguar. A few GT40s would be excellent however (Henry's Le Mans entries were a bit mob-handed after all!). Please email me via my website Building the Legend | A quest to build and race an exact replica of the 1966 Jaguar XJ13. nearer the 9th August and I can let you know how space is looking. The venue is in Staffordshire.
Ian, yes, careful of their power consumption, I think the major point is to wire through a power relay so you dont burn your switch out, and of course have thermostats so that they are not on unnecessarily and your alternator can keep up a surfeit of charge.
After a day making brackets etc I wired the first fan and it was hopeless - I recon I could fart a bit more air!
Time to do more research - probably need 500cfm to make any headway in moving the air from the engine area - possibly 2 8 inch radiator fans but then they chew a lot more electricity and make a load more noise - still better to be cool and noist than cooked!