Hotrod mag could only get a 15.1 out of a new 71 auto 440-6 bee and you have a mild cam, a vj and a bit of a vert on them.

Your tires if the newer BFG suck and if they are older they are aged and either way a good 340 wouldnt hook well.

Id be shocked to see quicker then a 13.9 as it is, but good luck.