Looking for a decent conversion kit from front
drum to disk on a 68 C body. I have done some looking online and just not sure what conversion kit to go with. Anyone used any of the kits available have any suggestions?

Need to know what is intended use, how important is originality, what is the rest of the powertrain capabilities, what is the tire/wheel package, what are the future possible upgrades, and what kits have you viewed so far to your liking?
This is where I would start.

I’ve used the DoctorDiff kits with success on several b bodies.

I've used a couple different drum-spindle to disc kits, no problems.
Most use GM calipers, rotor sources vary, might need different caliper fittings/hoses/adapters.
Generally a pretty easy upgrade.
Most if not all will increase track width, usually not much, but for wide ft rolling stock, may be important.

The factory disc route used to be the best way to go. I used to sell C body knuckles but sales were super slow so eventually I gave up on the C body crowd.

Just a cruiser 68 Newport convertible that needs front end rebuilt so might as well put some decent brakes on it. Not worried about being original. Has some 14 inch steel wheels and hub caps on it now but willing to change out if I had to. I’ve looked at the scarebird and some others that used GM calipers. Prices didn’t seem too out line for all new parts.

Your 14" wheel will be your biggest limiting factor on disc upgrades with your big car. Beyond that seems like there are many options, Choose wisely.
It is a worthy front upgrade IMO

My son has a 72 fury wagon. We parted one out to fix his existing one last year. He needed most of the front end for his project, as some was missing (someone else pirates my kids car to do what you're wanting? I dunno. It was before he had the car.
Last year at the Indy cylinder head swap someone had a set of spindles calipers caliper brackets but no rotors sitting out in their vendor spot for one of these cars // and I had taken a pic as I thought the asking price at the swap for what was there was nothing short of ridiculous. One of those "id like some of what that guy was smoking" kind of price.
But I know much of the suspension is the same and Interchanges on 65-73 for those cars and "everybody" says that there's something special about specifically the brake parts from the 73 model that's different and better than the rest of the years in that range, but what I dunno.
You might want to check out "for c bodies only" website for more info. I don't know if "c body drydock" is still a thing but they used to be real good for parts and Info on these cars as well
I do know there were differences in particularly the lower control arms and ball joints in the 74-78 c bodies, in those years I know the rotors and calipers Interchanged with the Dodge trucks and vans if the day/ I do know that the suspension between the c bodies and the trucks/vans was definitely different. The cars were torsion bar sprung, the trucks and vans had coil springs.

73 is special because of the 1 piece rotors.
earlier years have a 2 piece, but dr diff makes an adapter, either a bearing or something that lets you use the one piece.
and yes, those rotors are still used into the 80's for the full size vans.
there was someone that adapted a van spindle onto a c-body, but I am foggy on the details.
you will need 15 inch rims for that.
I am not aware of anyone but maybe scaredbird that lets you keep 14's