Didn't try, don't know if it would have 'fit'. I bought them intending to remove the bracket. If I had to guess I would say no for my car. I could not fit the larger HEI distributor due to firewall interference (I used a small cap w/external coil, it looks very original). I read where others have not had that problem.
Other mods? No, bolted right on. My car is a '63 so I had no problems with the alternator mounting bracket. Don't know what you have, it looks custom from the pic.
I do not know what your A/C will do to the installation.
My car had 2" ram horns and 2" dual exhaust prior to the change. I had to change the down pipes, the heat exchanger valve (I used a spacer), and mufflers. I chose to replace the tail pipes, but the new ones are still 2".
They manifolds came with gaskets. They would have 'fit', but the exhaust ports in my heads are larger than OEM and I used different gaskets.
I have an electric choke. If you have the standard OEM type choke, you will need to drill a hole for the heat tube (there is a place for it, it's just not drilled).
If you have Vortec heads, I've read the ram horns will not work with those, but I do not know from experience; just read it.