Back to work! I’ve been measuring for this chassis for the last two weeks, and created my third and (likely) final version of the build sheets last night. Not surprisingly, there’s more to it than slapping the tape measure on the frame table. In total, I needed to complete two worksheets and markup one assembly drawing:
- Front crossmember and suspension worksheet - determines the width of the crossmember, rack and pinion, standard or wide track A arm, and a handful of small assembly details
- Rear suspension and Fab9 worksheet - determines wide of the rear frame rails and axle housing and the location of suspension pickup points
- 68-72 Chevelle assembly drawing - they don't have a b-body Mopar drawing (yet), so I'm marking up their largest GM assembly drawing for length, width, etc. It's interesting how similar the Charger and Chevelle are in a few key dimensions.
To complete all these with a high level of accuracy, I needed to mount and gap the front fender and use the mockup 305 tire to determine the ballpark backspacing for wheels I have not yet ordered. In short, lots of time spent with the T square and tape measure, translating the location of features on the car to marked locations on the frame table, and capturing those dimensions in a linear method. Specifically, the front of the car is 0" and the rear is about 185", and the suspension centerlines, torque boxes, rockers, etc. are all measurements within that range. This is the best way I know to control and counter tolerance creep.
Front fender on, 305 at ride height 6" below the rocker. I had to cut the internal fender bracing to fit. The front suspension is pushed forward by 1.5".
For reference, max stuff with the original inner fender.
Cut and at ride height, level to the front. I'll dial in the suspension stance much later in the process, as everything has to be built level to the frame table.
This is my "evaluation pose". I'm trying to relocate the tire in the center of the wheel arch. Originally, the axle was pushed fairly far back in the slot, which I think was a styling consideration so the fender swept down and over a larger portion of the rear sidewall. I prefer the tire to be centered, because it satisfies my OCD. To achieve that, the rear axle moved forward 1.75". Wheelbase is planned at 116.75".
I'm headed to pickup a whole mess of 3" square tube so I can brace up the unibody externally and begin the cutting.
David