what cam for 340 bored 0.30 over?

DD, I have nothin but time to burn, I turn into a pumpkin before midnight though...work...patient, yea, nothin to get upset about

On the rear gear, for a street strip car, IN my head at least means 3.91's but your huge tires could use a bit more ratio (Numericaly high.)
The big catch hear is Hwy. speed. Something that will not have the engine rev so high at 65. And still work with the cams cruise rpm range. That also goes for the converter as well.

Exhaust manifolds are not street strip material or exactly a go-fast part.

Would you consider an OD tranny instead by chance?

Adam suggest a XE268 from Comp Cams. In the right set up, that cam should propel you into the high 12's. (I'm used to a 4spd manual car and would use a stouter cam for the street strip effort myself.) With the 28 inch tire, I believe a 4.30 gear would be about what your looking for. 60 -65 mph shouldn't be to bad.
(I'd rather 3.91's and a 26 inch tire. If I had an OD trans, I'd go and do the 28 inch tires and 4.56 gears. The OD ratio will feel like 3.14's, plenty low for the Hwy speeds and then some. 4.88 = 3.36. Max ratio I'd look at.)

I would finish up the rest of the build with a RPM or equal intake and bowl port my heads with headers bolted on. A bodies are hard with good fitment and I'd rather not use typical headers for this job. As in avoid the 3 tubes under the linkage problem. They'll do the job, though I would opt. for the next larger tube size myself for a little more top end punch with a 750 carb.
Take your time tuning the carb.