With a 2500 stall (now considering) , shift kit, 391's, and a small amount of ..... spray... high 12's?? That is if I didnt scatter the bottom end of the little 318!
Now you are going to the opposite end of the spectrum - the above setup is WAY different than your original question implied - what do you want from this car, daily drive-ability and manners or high 12s? 3.91 gears and a 3-speed are not going to be freeway-friendly at all, regardless of stall speed
Besides, all this talk is academic until you run a compression/leakdown test, IMO, cause the heads are just as much an unknown as piston vol, cyl pressure & ring seal
