The answer to that lies in a performance part that has been available for many years. An adjustable pinion snubber. Bolts in the same location and is adjustable upwards towards the floor pan. Like this.
I made mine when I restored a 68 Roadrunner and a '68 dart GTS. When I put my 70 Cuda on it, I had to modify the front brackets a little bit. Very easy to make..
Is he doing okay by you? Are you having problems?. I am out of the country right now and I tried to contact him to see if mine is ready yet when I return to America next month.
Already pretty far ahead if you look at my Build Thread......No Rust Car here....Very Happy
https://www.forebodiesonly.com/forum/threads/bluecifer-1970-cuda-b7-blue-restoration.37819/