I am just a novice here, but it will be interesting to see how you package a twin set-up in a 66-67 nova. I have a single T76 turbo in a 67 chevy ll and ended up with an air to water because of lack of room for an intercooler. I am sure it can be done as long as you are creative with the innerfenders and build a core support that is narrower that stock. Something with a longer nose would be a lot less headache.
Another issue I had even with the single turbo was the piping. I will say that my frontend is outdated because I used the Fatman fab pieces that leave the shock towers, but there is still not much room with a front cross member and rack for the pipes. I used the driver fenderwell for the down pipe and have some heat issues on the fender to solve and I have not solved the exhaust plumbing to the rear since the down pipe is on the wrong side of the subframe.
I did keep my air conditioning so that takes some of the room also... but what is a street car without air!!
Good luck with your projects I will be watching the progress.