See this for how Norwood and Van Nuys did the front clip in production, assembling it as a completed unit to the body:
http://www.camaros.org/assemblyprocess.shtml#chevMost other plants building conventional full-frame cars installed the front sheet metal "piecemeal" on the Final Line after body drop; this method is generally used by restoration shops putting a car back together:
1. Install radiator support with grille, header panel, hood latch and support; leave rad support-to-frame bolts loose.
2. Subassemble inner fenders to outer fenders.
3. Install fender assemblies to body and header panel/radiator support; shim at body to fit for gap and flush.
4. Install hood hinges to fenders.
5. Install hood, using it as a fixture to square the hood opening, secure rad support-to-frame bolts, fit hood for gap and flush to header panel and fenders, install diagonal braces, adjust hood latch.