Also realize that your 383 is probably bored .030 over already, so it is bored AND stroked. The problem with making the cylinder's diameter bigger (bore), is that using the same block, you can only go maybe .060 over stock, which doesn't equate to a lot of extra cubic inches (ci). The other option is to use a block with a bigger bore.
On the other hand, if you stroke the motor, you can add a large amount of ci. With your 383 (which used to be a 350), they bored it .030 inches larger (from a 4" bore to a 4.030" bore) so the diameter is a bit more, making it a 355. By replacing the stock crank (3.48" stroke) with a 400 crank (3.75" stroke), the piston now travels an extra .25" each time.
Hope I didn't confuse you anymore, if you have any more questions feel free to e-mail me.
[This message has been edited by 68Sedan (edited 08-10-2001).]