When the underbody structure is finished, and the body is off the frame, the body and chassis can be physically separated into different premisses for independent work, and do whichever you like first. Since there will be lots of dirt and dust around for a long time, I suggest doing the chassis first so it is finished and clean with a drop cloth over it before you are painting the body. My advice here is to store the engine out of the way and forget about it until near the end of the project. An engine rebuild ties up a lot of money that doesn't need to be spent until later, and a freshly rebuilt engine may not fare well if it sits around idle for some years before it may be used. For my first restoration the engine was the very last thing to be finished, and the day it was reassembled and installed I took the car for its maiden run on the expressway.

Chassis restoration is fairly straight forward stuff, as it is mostly structural and not much cosmetic. Maybe remove the floor and tunnel and hand brake parts while the chassis is still on the wheels. Gearbox, propshaft, rear axle and front suspension and all service lines come off in about one day. At that point the bare frame becomes a project of its own separate from the rest of the chassis parts, and about this time you may wish you had a split personality and could work on several things at once. You will spend lots of time cleaning and painting things. Plan on lots of dirty work clothes.

The frame will likely need some welding work, especially around the battery carriers, floor rails, and inboard surfaces next to the floor boards. As said, structural work, cut it, weld it, clean the welds up, and paint the thing. Suspension parts are mostly cleaning and painting, replacing some bushings and rubber bits, and get it all reassembled. If you think I'm trying to make it sound easy, I am. It is mostly time consuming grunt work, but if you get into the mode of trying to make everything perfectly beautiful for concours show, all bets are off on calendar pages.

The gearbox is apart in half a day and back together in half a day when you have the parts in hand (only a few hours total for me). Propshaft is mostly clean and paint, and maybe replace a U-joint or two. Rear axle will be clean and paint, replace seals and gaskets, and maybe you need to replace differential thrust washers, and install Speedy-Sleeves for the the hub seals. Leaf springs only disassemble if you want to concours pretty with painting, other wise replace bushings, clean and paint the springs. Rear shock absorbers often need nothing more than clean and paint, and maybe replace the link with the rubber inset ball joint. Reassemble rear axle and leaf springs with new rubber pads and shackle bushings. Clean and paint fuel tank and mounting straps, reinstall with new packing rubber, fiddle with the fuel pump, fuel lines and brake pipes. Find all the details on my web site. Leave the fuel tank straps loose, because it will have to be removed later for body installation.

Front suspension is a little more "tactical". Front shocks may need to be rebuilt if they leak (farm it out, not a home shop job). Swivel links may need new bi-metal bushings, some swivel links or swivel pins might need to be replaced if badly worn (rusted in the threads in a prior life). If the lower A-arms are egged out around the outer link bolt they may need welding up (or buy replacements). Cleaning, painting, new rubber seals, repacking wheel bearings, and reassembly, all pretty simple stuff. Rebuilding all of the brakes all around might be a day job or a week, depending on condition and parts needed. The master cylinder may or may not need to be sleeved. Steering rack usually only needs clean, paint, new seals and 6 ounces of gear oil, sometimes a couple of brass dampers and some shims, and maybe new tie rods ends. I am somewhat optimistic about a lot of this, more so if the car was previously in driving condition.

Clean and paint the tunnel parts, some of which may need a little rust cutting and welding repair. Buy or make new floor boards (find templates on my web site), sealed and painted, and get them installed (and sealed to the frame), along with the hand brake on the tunnel. Gearbox and propshaft install any time, before or after the tunnel (but do put the rear mount bolt in from the correct side so it can be removed with tunnel in place). You have some pedal parts to attend to whenever you get around to it.