[_Ogre]

you should leave the cab on the frame with the trans cover removed to position the trans & motor
get the motor/trans as high and far back as possible with a finger width max from firewall to valve cover
these trucks are notoriously front heavy, no need to make it worse

using an automatic changes everything, you can't use the stock mounts
if you have basic fabrication skills, motor mounts and a trans xmember can be fabbed for pennies
less if you have a collection of scrap steel laying around

a little 10 gauge flat plate and some 3/8'' heavy wall tubing you can weld this type up in minutes
these are similar to the 1st set i welded in my 58 way back before the internet
i did them in the truck with everything in place using 1968 chevy truck v8 mounts



the x-member is a little more complicated
when you remove the stock trans mount you also remove the cab mount supports
you need to build back in this support with the new trans x-member similar to what this TCI frame



this is my trans x-member with bracing the cab supports and a drop out section for the trans mount