I were going to "soup up" my B engine back in the 70's what cam would I have used ?

Crane Fireball.

Direct Connection Purple Shaft .509 lift 292 duration Hydralic cam.
Oh, and don't forget the Holley #3310 750 cfm, Edelbrock dual plane, and some Hooker Headers attached to a pair of Thrush mufflers.
All while listening to your Radio Shack 8 track player, with some
KISS or maybe a little Foghat...

You question is a bit vague. Some will say a purple shaft.

I like old vintage cams, big and stinky but some dont.

There are from time to time some good old vintage cams on ebay, her is a current one for a BB and it almost looks to me like you could use a new oem spring or still a single, but im not a BB or cam expert but here is the link.

Pretty mild but above stock it seems.

https://www.ebay.com/itm/Big-Block-Chrysler-Dodge-MOPAR-V8-Speed-Pro-CS-181R-Performance-Camshaft-Cam/182798760006?epid=23009291102&hash=item2a8fa7b846:g:LkQAAOSwXedZz6jF

You should probably post the combo you have now and what your expectations are.

Isky 1012B was popular at the beginning of the '70s.
The 1012C was another one I heard about a few times.

Using a vintage Weiand intake and cal custom valve covers on the B engine (400) I’m putting in my ‘73 Barracuda. Thinking of keeping Old school cam too. I’m not racing so it’s not particularly important that my combo isn’t awesome.

You're definitely well on your way.

Those look like 346 head castings from the "II"....

Don't forget the Mallory Rev Pol, Voltmaster coil, paint the headers white, etc etc. Or maybe Accel dual point + super coil + yellow plug wires that always seem to be covered with grease stains. Definitely consider using solid core plug wires to cause as much radio interferance as possible. That's how they did it back then....

from the '70 Hustle Stuff catalog * RACER BROWN SSH-25

http://www.4secondsflat.com/RB%20Cam%20Specs.htm

Zippy nail it
OP, that old intake may make you change your mind on using after driving it a while
I have one of them on a new small (464C.I.) stroker (3.91 stroke) pump gas motor 440 motor now with a 850 DP, I'm anxious to see how it works

Use the 509 so it runs like crap with that carb. Then you'll get sick of driving it and park in the shed where it will become a barn find in 30 years. I think the 509 cam created the barn find Mopars since the engines ran so poorly with them. The 509 + 850 DP combo turned lots of nice 440 engines into stinky, plug eating piles back in the 70's.

But the .509 cam with a Holley 3310 vac. sec.Edelbrock CH4B//727 w/3000 stall convertor/3.91 8-3/4 is the way to go.
I used that combo back in the day in my factory stock headed 440 C Body, and it ran low 14:20's @99.5 MPH, in a 4600 lb. convertible...on street tires with full exhaust as well.

Yep these are the hipo 346 heads ! I have actually been considering using some of those other components you mention that are available to me

That's cool!

I have no idea what this intake will do. The reason I got the 400 is for future stroker build. But that’s not a priority right now and since this engine I got is running in decent shape I’m going to run it. I’m the carb I have is a 700 annular discharge.

The 509 is definitely an option !

Absolutely! Just like that Kiss Alive II !

It was a barn (field) find when I got it ! Lol

your safest bet is the old street hemi grind.

Do you want to run a hydraulic flat tappet, solid flat tappet or which type cam and lifters?
I would stay away form some of the older cam grinds, especially the Mopar Purple shaft JUNK
I see so many people on here advocating them(they have always, until recently, been cheaper in costs than any other brands out there and I wonder if those people have ran anything else
I sold a friend a Mopar Purple Shaft 284 street hemi grind for a 383 motor going into a 1968 Charger with power brakes, he owned a automotive garage and it was for one of his bigger commercial customers Son car. I help him degree it, it had right at 4.5 inches of vacuum idling at 850 RPM in gear, enough to stop once good in traffic and not again in traffic very well
He ended up buying a R.V. cam kit and installed himself straight up dot to dot
The kid ended up wrapping that car around a power pole within the year of the motor work
Take your time on the cam selection and make sure and degree it regardless of which brand or grind you choose

That's strange... must have been something else wrong since you degreed it for him. Huge vacuum leak maybe? I put that exact same Purple Shaft cam (284/.484) in my basically stock 383 rebuild. It idled with a very minor lope at 13" vacuum at 750 rpm!