I
think Joe is running a Proline widebore which uses an Alan Johnson block and heads. They build a Hemi version which is pricier and more expensive to maintain. $77,000 IIRC. Used ones are around $50K. Several guys are running the Hemi version.
They might use a BBC waterpump and valve covers but little else.
Drag Racing Engines - Turbo and Supercharged - Pro Line Racing