350 and 400 are diffrent castings. You can only bore either of them so much. 60 over is the limit for production castings. You will start making cylinder walls thin and blocks weak. The cylinders add to the rigidity of a block. You can get a 396 out of a 350 with an aftermarket crank with the strokebut not by boring. They are just simply not made with that much material to bore it out big. Why do you think people go with the popular 383 or stop at 388. Because it is all you can do with a 350 block and stock 400 crank that has been turned down to fit in the 350. People just don't go with the 400 block because the cylinders are bigger making them closer together and less coolant can flow between them making the 400 run a little hotter.

 

gotcha, thanks mike.

 

And thank you for giving ScottD hell since I have been slaking

 

haha not a problem man, not a problem.