The easiest way to do it during an engine swap is to put the headers in first and tie them up out of the way. Then drop the engine in, untie the headers and bolt them up.
I'd also consider not running that heat wrap stuff. It's terrible for the longevity of the headers especially if you ever get them wet.
I'd also consider not running that heat wrap stuff. It's terrible for the longevity of the headers especially if you ever get them wet.