302, 351w will swap without too much work..
Engine mounts, rad/shroud, exhaust, engine harness, throttle linkage, just to name a few. If your truck is a manual shift, you'd need the flywheel from the V8, 4.9 is weighed/balanced different.
05 F250 C/C FX4 6.0
1969 Firebird Trans Am
2003 Hayabusa GSXR1300