Yo 427,
I second, third etc. the opinion that a new block is the way to go. I went with the Dart Aluminum for my GT40.
Here's a pic......Oh yeah Webers too.
And a stroked 351 to 418 with downstacks, fuel injection etc. for the Daytona...
The Daytona engine was and is scary fast 560 HP 580 ft. lb. torque, the GT is a work in progress but, I have high hopes.
TR