Hi Ben240z,
I have just read the UK Z club magazine article that included your Z, and after seeing your hillclimb video very exciting stuff. I am currently building a 280zx wide body race car in New Zealand. The car is loosly based on the IMSA Cars, and includes FRP guards, quarter panels, doors, with carbon bonnet & deck etc...
As for the engine, the current specs are as follows: F54 Block, N42 Head - lots of work, custom inlet manifoled with 6x50mm EFI throttle bodies, ARR dry sump system, CSR electric water pump, Nismo damper, LD28 crank, 240z rods, all the normal full race prep. plus lots more, Nismo valve springs, Nismo cam sprocket, ARP bolts, oversize titanium valves, 50.8mm SS Headers, 89mm forged pistons, 5.5" tilton triple plate clutch on custom flywheel, HKS 1mm head gasket, Motec M800 ECU, etc, etc... Final compression ratio yet to be confirmed but looking at something around 12:1... and hoping for ~300bhp+ engine will be run in on engine dyno with final tuning on rolling dyno, so I will post the results once known... It should be alive earlyish next year.
Look forward to more updates on your car,
All the best Grant