13's, stock '71 318 short block.

You can reach the 13's and probably even the 12's with a stock type 318 bottom end, the 13's fairly easily. Just don't be disappointed if it doesn't get there right way. Most of the guys who have mostly stock engines that run well might spend a very long time trying lots of little tricks and using their heads to trim a hundredth or two as opposed to going broke spending big chunks of money to no good end.
Some of these guys who do, may own the same car for years to get where they are, and are usually the guys everybody respects for their tuning ability.

I saw a stock eleminator class 67 Coronet with a 318 2 barrel running very respectable times at our 1/8th mile track. All steel, Carter or Stomberg 2 barrel, and was only shifting it at 4800 rpm (!) and still turning times that would put a lot of 340 cars to shame. It can be done!
Alan