As I’m fitting the new engine / transmission, I’ve had to make a lot of modifications to the frame to fit everything in. The bellhousing and transmission are a lot wider than the unit that was in my GT6, so I had to cut a lot of the frame out to fit.
While doing this and test fitting the whole unit in the frame, I noticed a considerable amount of flexing in the middle. This is mainly due to the fact that I have the frame supported at the far ends instead of the wheel areas, but still it bothered me.
Another thing that really threw me for a loop was just how thin this frame metal is. The metal used for the frame is literally ~1.9mm thick, or 14 gauge sheet metal. I’ve seen body work thicker than this.
I decided since I was cutting out so much, the metal I put back would be considerably stronger. This is mainly because the new engine will have ~300rwhp to start, which will put considerably more twisting force on the frame. It weighs 120lb less than the stock cast iron unit, but I believe stronger is better in this area.
I ended up using 3/16″ flat bar to rebox the frame, which is over 2x thicker than the stock steel. You can see how I double boxed it in the picture below, and then the finished product.
