Your ride but,, if it were mine I would just tune up what you have.
I'm not against MII at all I had one for several years.
I still have one in the shop in a '40 that I haven't driven yet.
It isn't a small job changing it over. I once had a drivable rod,, tore it apart and lost interest. I ended up selling it that way.
If you do it use your measuring tape before you buy to get the ride height right..
IMO
TMJ
A friend of mine used the Fatman Fabrications hub to hub kit in his 54 Dodge truck and loves it.
I took a tour of Fatman's shop in North Carolina a couple of years ago, very impressive.
Call and talk to them before you order anything, they're very helpful
I was looking at their product on-line. They have a kit that is a bit narrower than normal. Something to do with tires not rubbing the fenders, if you are lower than normal. Looks like they know what they're doing.
I read a story once where the strut rod bracket welds broke at the frame on a 40 with IFS. Don't know what make it was. Those frames are thin in that area . If you do the conversion, I would beef up the frame in that area. I have a stock front end with discs and power steering on my 39 and it works fine. Just drop the wishbone ball about an inch to give more caster-better handling.
I had a Fatman Ultra low crossmember in my 47 Convertible and put a lot of trouble free miles on it. I do know of cases where cracks have developed in the frame and it was blamed on the super heavy duty tubing used by Fatman. I'm not an engineer or a qualified welder so I don't know the circumstances or what really happened but I have seen the cracks. The Welder Series stuff gets my vote though. Paul's been doing this for a long time and has a great reputation. You can buy his stuff already weled up through Horton's Hot Rods in Milton.
__________________
My wife wants me to see things from a woman's point of view, so now I spend a lot of time looking out the kitchen window