Putting a 393 cleveland with 4 into 1 headers in a Falcon Xy help

[RAWXY]

Hi guys,
Just would like some tips on putting my engine in my falcon Xy replica.
I have a stroked 393 cleveland with raised port heads, pacemaker 4 into 1 headers (inch 3/4).
I've been told that it is very tight fit and that I should maybe bolt up the drivers side headers before I drop the engine in?
Anyone had any expierence with this type of install??
Any advice will be a big help.
Thanks