There's a fellow in the Houston Area that if I recollect right, put exactly the same year and type drivetrain in his 69 Firebird. 02 truck block 6.o with the 4l80e.
I don't know if he posts here. But The car seems to run and drive very well. It just barely fit under the hood due to the tall truck intake.
I could try to help you get in contact with him if you like. He is a member of the H.A.L.F. club. Houston area legendary Firebirds.
Here's a picture of his car.
