I had a 92 F-150 reg cab, long box, 4X4, 300-6, 5 spd with a 8' Western, I plowed for 4 years with that truck. I bought the truck with the plow on it and the front end sagging badly with the plow on. So as soons as I got the truck I went to the auto parts house and got new coils for a 92 F-150 S.C. 4X4 long box, V-8, heavy duty ac, and auto tranny. They had either standard or heavy duty, I got the heavy duty ones and got 3" of lift out of them, and then truck only sagged 2", so it still sat about an inch higher with the plow up than it did when the truck was completely unloaded.
I just had a set of heavy duty front coils put on my 82 F150 two weeks ago. I also bought mine from a local spring shop.He said they were the heaviest ones I could put on my truck and the cost was just under $190.00 (installed). The truck looks much better with the new springs (about the same as a 250). I know you'll be happy when you get yours on.
I would purchase from local parts store , you can use coil springs for a 2wd 1ton put them in every 150 ive had easy to install as well cost wise moog sells for about 90.00 a set , takes care of any issues with sag thats forsure intil they settle the front end does set a little higher without the plow but no biggy they will settle.
I put CC844S TRW springs in my 93 F150. Got a 3" lift. Holds the plow GREAT! I had the rear springs done...added a leaf and put the 1 ton helper in. The truck overall is 3" higher empty. I hang the Fisher and the front barely drops. Carries the plow great! No bottomming suspension and steers good. I can load the bed without much sag. When the truck is empty (no plow) it rides slightly harder but not like a rock. Handles 100% better too! You must get the springs with the "S" in the part number. TRW makes them but Moog does not! The "S" has about 500 lbs more capacity. The application is a 4X2 F250. They are the same height as the HD F150 4X4 spring and go in easy. If you are in the NYC area I will happily help you! Good luck. I wish I did this when I first got my truck 3 years ago!!!