Before writing off your block, check out the size of the crack using a crack dye penetrant kit. It could well be possible to get it repaired using 'cold metal stitching'. Good luck.
Wow, nice collection of parts to start your project with, one of my favourite all time cars. I wish you every success with your build, whatever you decide your budget is, at least double it! With regard to the wheels I echo Mike's comments regarding magnesium, though I did race a formula 3 car...
Central spine chassis may be OK for lower powered cars like the Elan, but think of V8 powered examples and descriptions of wierd, spooky and terrifying handling come to the fore e.g. Lotus 30, De Tomaso Mangusta.
Hi Mike, hope to see you there Monday. (Showing a couple of motorcycles on Sunday). Let us hope the weather is kinder to us than the last few weekends!
Other tracks may be more exciting to drive e.g. Oulton Park (my favourite), Thruxton and Knockhill but none come close to Silverstone as being suitable for a modern F1 GP when you start to consider location, access, capacity, track safety etc.
Shaun, before I retired the whole computer building was protected by a Halon system installed in the mid-1980s (in fact it had to be fully tested by dropping the entire system at the insistence of the insurance company at some considerable expense and downtime!) but this system had to be changed...