1952 Pickup Street Rod project

[dsraven]

3/4 is probably enough on the rack. since you are running urethane mounts I would see what you have for clearance from the hot exhaust, maybe run a heat shield there and on the starter if it is close. there are some factory starter shields out there if you peruse the wrecking yards. one of those under floor exhaust shields from a car may also be reshaped if you need something for the mounts. maybe reshape the steel line on the rack and see where you're at there for clearance. on one of my builds I welded some flat bar to the frame and then bolted the engine mounts (frame side) onto those. then they could be unbolted easily for quick engine removal and also new holes could be drilled should there be a height adjustment needed or an engine swap to a different engine block style, etc. just a thought.
for engine height, I usually try to keep the oil pan above the frame in the same area. if going over one of those crazy high speed bumps or trying to miss that garbage in the middle of your lane the frame will hit rather than your oil pan. do you have room to go up more or you'd rather not? what about the driveline bellhousing, will it interfere with the floor if the engine raises?