FMX, In regards to your firewall, If the camaro was put in rite, you should not have to do any cutting on your firewall. I'm not sure how wide the camaro is,It may be too wide for fender clearence when every thing is in place.I have a 68 camaro sub. under my 40 chevy and if I don't drive into driveways at an angel my fenders rub the tires. (ya learn to Live with it ) The sub. should have been narrowed when put in.would like to switch to disc brakes in front ,but no clearence. And I'm not about to rise it up.(nose bleed LOL) Your 48 may be wider than the 40??? Never compaired them before. Not trying to scare ya but its something to be aware of.