I looked at the 58 - a hard freeze at the moment makes it difficult to do much, especially crawling under!
here's one reference - as everything fits the same on all 55-57 1/2T's, the distance from the back rivet of the core support bracket to the front rivet of the 1st cross member should be the same on all .... the only early frame [57] I have now is hours away at a friends
I found a pic of
a 5-7 w/ V8 - the distance the rad is moved back is shown by the flat sheet metal piece just in front of the rad tank - that position will be evident as the area where there's a 3-holed reinforcement spot welded on the outside of your 55 inners .... and
here's one of my 58 shroud, making up about the same distance
yes, I'd forget about that 'front of dash' measure, could be off from variations in cab mounts or other things
Bill
