1962 s series 6.1 hemi

that's looking great! I noticed you have cut out the original firewall before plating it, in the ACT, (Australian Capital Territory) for those in the US, we have to leave the original in place and plate over the top. Rego here have some odd ideas! Sub frame connectors are another problem, here that is a chassis and then requires the car to be registered as an individually constructed vehicle.
Have you thought about installing torque boxes while you're at it? Everything I've read out of the states make them sound like a good idea, try the link below. I found him great to deal with.

www.sheetmetalstuff.com

good luck, Marty