Hotrodn.. what those folks are trying to explain is that the chassis you have was for a style of car called "Pro Street". This means that the chassis was cut up and narrowed drastically to allow really - really wide rear tires with a really narrow rear axle with a 4 link type suspension.

If you're not after that particular look, then the frame you've purchased / chosen really could be prohibitive to you actually building a "regular" street rod. And those bodies you are looking at just might not mount. But Duane will know for sure. HTH