Finally, everything is prepared for the actual connection of the new front end and frame section from the Olds, to the 58 Chev frame. The inner faces of the frames match very closly, with 1/4 inch O.A. difference. Because of the boxing of the Olds frame, it was a question of which way to match in the frames to have the least effect on the strength, and the brackets of both the Chev body mounting points, and the Olds front end brackets for control arms etc.
With frames in position and the fish plates made and everything lined up, I started to weld the 78 Cutlass front end to the 58 Chevy frame. Now, I was able to fit the fish plates and weld accordingly.This took some time as I proceeded with care but in the end was indeed a red letter day.
With these pictures, you can start making sense of the previous statements about the fish plates and the inner and outer frame faces. The inside is virtually a perfect match up. You can now see how the outer wall of the Olds frame, has been extended straight back to ‘square out, against the front body mount bracket. Ultimately, this creates a fairly smooth transition between the frames, and hides the differences and joint nicely.
Here’s a twist you may want or NEED to consider. Some jurisdictions mandate that you MUST bolt through any frame splice, to provide a safety system if the welds were to break, the bolts and fish plates would keep things together until you get to the side of the road. While many of us look at this as rediculous and unrequired, remember one thing. Rules like this are usually created due to someones failure. Consider some of the worst welds, or worst engineering you’ve ever seen, then decide where this rule came from. Unless you are building a beautiful show chassis, this is not a bad safety net. Done right, it doesn’t create an unsightly look for a street car.
Check your local licensing or vehicle inspection to verify your local requirements.