Choppy idle and great low end torque, shouldnt be in the same sentence when applied to a short stroke engine like a teener.
Low end torque requires the engine to ingest a lot of combustible mixture,trap it early,compress it into a little tiny space, lite it to burn creating as much pressure as possible without detonating,on the end of as long a lever as fits in the engine, so that the expanding gas can push for as long as possible.
A choppy cam doesnt trap early(thats partly why its choppy).No trap equals no torque.A large total-volume chamber sitting on a small swept volume cant compress.No compress equals no torque.A short arm releases the pressure too soon. No pressure equals no torque.
The point is,that a teener, with no other changes will lose low-end torque with every next bigger cam you put into it. And it will lose it plenty quick.
Now,I see that higher compression pistons have been installed.And thats a good thing.It will pull up the low-end torque.Maybe youre ok with giving some up for the choppy idle.
Of the cams you are contemplating chose the one with the earliest intake closing event to trap as much mixture as possible, and that will likely build the most torque.The 340 cam duration specs are a pretty good balance between power and torque, if a little shy on lift.
If you want what you want, I think you will need a new personality for your 318. A stroker kit will do it.It does it by increasing the swept,increasing the stroke,and increasing the pressure.Then you can give up some of that torque with a bigger cam. This will give you the choppy idle you want,AND a net torque gain, and as a bonus,more horsepower too. It gets a bit pricey though.
A bigger motor will do it too, for all the same reasons.
Or you can shave a BUNCH of weight off the A, and keep that teener, with any cam you want.
Personally, Ive built several teeners for my personal cars and I wont do it again.