Here 3 of my Projects out of 9
Put a solid mount on the driver side of that 440 going in the pickem'up. I had to replace a fan shroud first time I got on mine using the stock rubber mounts. The torque still flexes the frame but a steel mount controlled it enough on my truck (86 short box) This was with a mild built 440 and a OD truck 833. Hope this saves you the cost of a fan shroud.
By the way I have tortured my OD trans in this truck and it shows no signs of wear or breakage. 31" tall tire 9 1/4" sure grip. Added a few leafs also.
When you get that swap together you truck will feel light as a omni. have fun.