[bduff509]

If a 396 is the same block as a 454 you may not have to move anything. My son & I just pulled a 350 & stuffed a 396 into his '80 Camaro &, outside of the tight fit, it went right in. You may have adapt your fan shroud as I believe the 454 is going to sit a little higher. He's also going to have to go to a 'vette style hood for clearance but you won't have that problem with a truck. I had a 454 in an '80 Suburban. I got about 6-8 mpg. It's a great towing motor, lots of low end torque but, if it's horsepower you're after, you're better off with the 350 unless you want to spend an obscene amount of money.