With the 3" chassis stretch almost completed, the next step is the 3" stretch of the engine cradle. However, those pictures are on another memory stick somewhere here on my desk so until I find them, I'll post details of the progress to reinforce the chassis in way of the rocker panels. As you may recall, this project will be a 355 Spider so I have been researching and reading as much info as possible on the topic of chassis reinforcement......... and there are certainly many schools of thought on this topic. With some input and suggestions from other forum members, I have designed what I hope will produce a strong structure that resists bending and twisting without reducing ground clearance or interfering with the 355 body.

The reinforcement structure will be fabricated from a combination of 3" x 3" x 1/8" HSS and 3" x 1 1/2" x 1/8" HSS with 1/4" plate gussets in the corners for added strength. The front end will follow the curved surface of the wheelwell / A pillar, replace the factory sheet metal rockers, pass through the B pillar and then proceed upward at 60 deg to intersect the upper rear frame rail just forward of the rear wheel.




I know it may be hard to visualize the part without the drawing of the chassis included, however, that part of the 3D model is still in progress and I hate to post incomplete drawings.

The drivers side was started first by removing the original rocker sheet metal. I left about an inch of the top so that when the new structure is fitted, it will be at the same height of the original rocker panel body work. I wanted to be sure the new structure was not so high as to interfer with the 355 rocker body panel.



We used a laser to shoot a straight line around the A pillar and B pillar before laying down some masking tape to assist in cutting the correct profile.




The bottom edge of the original rocker sheet metal was left as well and then folded upward to give some extra support to the new structure. The new structure will be welded along the top line of the rocker sheet metal, along the bottom flange of the sheet metal as well as a few plug welds along the inside door sill.




It was also necessary to remove the seatbelt anchor point. This will be added to the new structure in the factory location. This is a part most Fiero enthusiasts never see and never want to see.




Once all the required sheet metal was removed, we test fitted the 3" x 3" x 1/8" HSS to see how it fits at the pillars, along the door sill and at the upper rear frame rail.






We are happy with the initial fit so now we will fabricate the structure completely and then fit it to the chassis and secure it in place. With the design and arrangement of the structure, the entire part can be fabricated and welded 100% off the car before final installation.

Once it is complete, we'll post pictures of the final installation of both sides. The next step will be to design and fabricate a structure to secure to the engine side of the firewall which will strengthen the chassis transverely by tieing both the upper and lower frame rails together. Once this is done, it will be time to make the big cut and remove the roof.

edit: remove photo of family member

[This message has been edited by Yarmouth Fiero (edited 02-23-2015).]