48 speed shop,

Putting the engine and transmission in together worked best for me. The LONG assemble gave me a better chance to line everything up properly.

The transmission output shaft is a good measuring point to get the rear of the combo centered in the frame.

I did this without a front wrap on, which made it much easier. Your transmission needs to clear the cab floor and your distributor needs to clear the firewall, these are critical areas.

Wise use of a floor jack, a level and a tape measure will insure success...measure at least 5 times before you weld, tack, or bolt anything up.

Good luck and stay confident.

Stuart