Progress. Slow and steady progress has been the theme since our last update. Mike Ryan has been plugging away on our 1978 Malibu, Project Grandma, with the goal of getting the Chassis Engineering mini tubs built this week. First though, there were a few loose ends to tie up before we could put Grandma in the tub – errr, I mean the tubs in Grandma. We’ve got the TRZ front suspension, QA1 Shocks, and Aerospace brakes bolted up, and that article is about to be deployed. Until then, check out our daily progress.
The GM G-Body is a very easy chassis to work with as a outer perimeter full frame car. The challenge with a 25.5 car is the work that is needed with the frame: the boxing of the stock frame and the addition of the inner frame rails. No matter the SFI spec, we’d need plenty of stiffening for the chassis to take the brunt of the 1,050+ horsepower 555 cubic inch Pat Musi/Edelbrock engine.
We also got a bunch of goodies in the shop today, courtesy of our friendly UPS man. FAST sent us a dual wide-band Air Fuel meter so we can make sure to get the correct mixture of combustion in the Edelbrock 555. Moroso sent us a nice switch panel, and Edelbrock hooked up Granny with a Edelbrock Progressive Nitrous Controller, Purge Kit, and a 2nd fancy Edelbrock silver bottle. Nice.
The first thing we did was raise the body up off the chassis. This was 10 bolts. We have Energy Suspension body bushings – some recommend aluminum bushings for a hardcore pure drag racing applications, but they are about $200, and the easier fix is to just weld the chassis to to the body in 5-6 spots to eliminate flex. We’ll be cheap. Plus, the Energy Suspension bushings are very strong and we’re confident they’ll hold up to many seasons of drag racing.
Mike started off by cutting some raw steel to the right shape needed to box the frame rails. Once again ourCornwell Plasma cutter made quick work of another job and before long a rough-cut piece was pinned temporally to the frame to be welded in. After spending a little more time making some finishing pieces Mike welded in the newly added metal.
This was our contraption for getting the body off the frame, while keeping the frame high for ease of welding. Take one Bendpak lift, about 5 tall jacks, and a small whisper to god to pray this entire thing doesn’t come down on your head. We hope our insurance company never reads this.
Here’s our virgin frame. It’s a C-Channel, stock G-Body outer frame that is not boxed. We need to box it for SFI regulations and for chassis stiffness, as well as to provision something for the the frame rails, control arm supports, driveshaft loop, etc., to weld to.
The first thing Mike started with was “capping” off the editing “L” shape of the front and rear frames. This was simply a plasma cut piece of steel sheet we used, templated and cut to fit. Then we began cutting the long strips of steel to box the frame.
Here’s Ryan uses his favorite tool – the Cornwell Plasma Cutter, to cut away the strip of steel necessary to box the frame. We think it’s a cool shot because of all the radical sparks. We also think it’s cool that the old IKEA desk Mike has stolen as a work bench isn’t on fire. Yet.
C-Clamps holding in the boxed frame rail prior to welding during the fitting process. It’s important to get them close and right before firing up the welder.
We used a combination of TIG and MIG welding for the boxing process. We TIG welded the caps, and MIG welded the longer boxed sections of frame rails. Do whatever you feel you are better at if you are doing this at home.
Here is the completed and boxed left side frame rail. You can see the “half dollar size” steel hole Mike had to close up while building the end cap. These little details aren’t necessarily safety or SFI requirements, but they make a big difference in stiffness. It’s it better to do the job right even if it takes a little longer?
Coming next – and finally – how to build Mini Tubs with Chassis Engineering steel tubs.