I have to vote for the up-from-the-bottom method as well. Transmission, 440, headers, steering, accessories - all installed in just a few minutes on my patio (note: It got dark while I was inside having dinner). I've done plenty of "in-from-the-top" installs and I'll never do it again.
The 440 with everything ready to go, sitting on jack stands
Push the car up close (not hard. Doesn't weigh anything without the engine and trans)
Drop the old /6 K frame out and lift the car with the hoist. Use the hoist to roll the car over the engine
Lower the car, 4 bolts for the K frame, bolt up the UCAs, hook up the brake lines, couple bolts in the cross member, pop the T-bars back in. Easy-peasy.
Honestly, the hardest part was getting the old K-frame out from under the car after I dropped it out. :glasses7: