looking at you post makes me ask two questions;
1. what year of S/C do you have / is it the original engine?
2. are you sure he did not say that the "camshaft" not "crankshaft" is walking?
as i am looking at my ford service manual on the exploded view for the V6 engine, the only item in the short block that has a thrust plate to stop walking( which is what a thrust plate is designed for ) is the camshaft.
if you "misremembered" about what he said and it's the camshaft, the hardest thing you'll have to take off to replace the thrust-plate is gonna be the harmonic damper/balancer. you should have enough room with just the fan and shroud removed to accomplish this. pretty much after you get the balancer off, pull the timing cover and remove the chain and cam-sprocket. after that, pretty much pull the 2 bolts off and the plate will be the thrust-plate.
if it is your crank that's walking you have HUGE problems. that means that the main journals on either the block or the crank is TOAST!!!
if I'm off on this or you have a V8, gasp!, sorry to waste your time