It weighed 300lbs more than a 350 gasser or about 60% heavier.It was a normal 350 gasser with new heads, no special 454 block
My father ran 5.7 diesel’s and I can attest that outside the motor mounting points and the transmission mounting pattern you would be hard pressed to find parts that were fully interchangeable
Our neighbors claim to fame was being able to muscle around a 350 without a hoist, he couldn’t budge the diesel.