Datsun Z. Pt 1. Replace frame rails with Box Section steel - 240Z 260Z 280Z

Hi All. Apologies for the sound quality in the video. I got hit with a copyright issue with the music so had to overlay RUclips approved clips which are loud in comparison. Hope it doesn't bother ye too much. Thanks.
Part 1
This is a nice and easy approach to replacing the frame rails on your Datsun Z but could be applies on other makes and models also. It is suitable on a car with different levels or flat floor using the existing location of the chassis rails.
The car here is a Datsun 280Z 1977 and the steel box section is 70mm x 70mm.
Hope you enjoy the Video