360 or 383?
Also, with the 383:
* You'll have around 50 lbs of extra weight up front.
* Piston and intake choice is much smaller, if you find them.
* Less room in engine compartment. (Plugs & headers.)
* You have the option of a built 904 for the 360 that would be about .15 faster than a similarly built 727, if you decide to go that way. (With same converter specs - converters don't interchange between transmissions.) Only 727's were available with big blocks.
Focus on a well balanced combo that's easier to build and reliable.
I vote for the 360.