I cannot speak directly about Nova's handling with a straight axle, but I do have some experience with solid front axle setups.
I had a '40 Willys coupe I built with a 4" dropped front tube axle. It ran coilovers and had a new Flaming River Vega steering box. It was a rear steering setup and had your normal drag link and tie rod setup.
I changed a few things trying to reduce the angle of the drag link from the pitman arm to the right front steering arm. The flatter the drag link is at normal ride height, the less the bumpsteer.
Most kits today have one lower steering arm on each side. The right side steering arm usually has two holes. The inside one is for the tie rod from arm to arm and the rear hole is for the drag link to attach.
What I did on my Nomad Gasser was I purchased a second steering arm and mounted it to the top two bolts on the spindle. This let me run the drag link above the front leaf spring and the drag link was parallel with the tie rod and had I kept the Nomad and not sold it, it would have been a pretty good handling car, considering it was a straight axle setup.
Dan's '55 Nomad Gasser Pictures
Here are some pictures of the work I did on the Nomad and front straight axle.
The axle kit I had on the Nomad came from Bill Merlock in Arcadia CA. He's been making straight axle kits since the '60s and came highly recommended. At the time I did the Nomad there was only one other available, MAS up in MN and they did not have a good rep for larger cars.
Bill had a great kit and his tube was the same as most others now, but when he made the tube and prior to welding on the kingpin housings, he took a piece of 3/8" bar stock and pressed it into the end of the tube all the way through to the other end. This bar stock now turned the round tube kind of into an "I" beam. He said that for the weight of a '55 Chevy, you do not want to bend your tube axle. I thought that was a great idea and the thing that sold me on him as my vendor. He also worked with me on extra parts like steering tubes that I could tap myself and make my own steering links.
On my Willys, which I drove 16k miles in two summers including one 6300 mile trip from MI to CA via Bonneville, it handled and drove very well. This car only had a 100" wheel base and was a bit choppy, but even a IRS front end with 100" wheel base and my weight distribution would have been a bit rough.
I set it up with caster only as the camber cannot be set without a frame machine. So if it's built with the kingpins at the correct angle, caster is all you have. Okay, you still have toe in to adjust, but every car has toe in, not just straight axle setups.
I played with the caster and finally ended up with 6 degrees positive. This allowed it to track great going down the road and I found it was easy enough to steer. There several times during my 6300 mile trip that I was well over 120 mph and it never once gave me any indication of looseness or that it was not stable at that speed.
So after that experience I felt the Nomad would be a good candidate for a gasser. With an additional 15" wheel base over the Willys, it should have riden quite nicely, relatively speaking...
I would not hesitate to do a Nova gasser and that is exactly my plan on my '62. Also if you flip the steering to the front, you can get the steering linkage out of the way of the pan. I would also use the Flaming River box as it was very easy to setup.
As a side note on steering boxes. When setting up my Nomad from scratch wtih the Flaming River Vega box, it had about 3.5 turns lock to lock. When I started to do the setup with the pitman arm and steering linkage, I took whaterver the exact turns lock to lock were and split the difference. That then became my straight ahead steering setting. I notied that with the frontend off the ground, it was a bit loose in the center and if I turned it about 1/4 turn it got a bit stiffer, or it had a tighter feel. The other direction off center by a 1/4 turn did not give the same feel. I called Flaming River and they set me straight. They said that "ALL" boxes have a slight high grind that is usually at center or just a bit to one side or the other. This high grind is the slightly tighter feel that I felt. They told me to move my straight ahead to the tighter spot and adjust from there accordingly.
Most of the straight axle frontend kits do not have spindle hard stops to stop the spindles in the lock left or lock right position. These will have to be made up and welded in when you have the frontend all setup. You want the spindles to stop in full turns, not the steering box.
Okay, that got WAY out of hand with my original "short" thoughts. Sorry for the rambling again, again, again, sorry!!!
If you have any questions that I might be able to help you with, let me know and do take a look at the Picture trail link to my photos. I also have about 100 more build pictures of the Nomad, but only uploaded the more relavent ones to my Picture Trail Nomad album.
Thanks for putting up with me...