Quick questions Magnum Heads - Is there a difference between 318 & 360 magnum heads?

The Magnums are great for mild/moderate builds. They have a big pushrod pinch though, so flow can be limited on higher HP builds. All in all, IMO, they are a step up from bone stock LA castings, because they offer bigger valves, smaller chambers and higher ratio rockers. I'm a BIG proponent of the shaft mount rocker system, so that's a statement coming from me. Another advantage to me is, the magnum stuff.....like the timing cover and water pump will accept the serpentine belt system. I'm putting it on my 318. I don't wanna spend a lotta time huntin up v belt pulleys tryin to find the right ones.

Lastly....if you find some that are NOT cracked, unless you do something stupid like overheat the hell outta them, they probably will not crack. Also, cracked ones are not necessarily junk. If the crack is only in the valve seat, and does not extend into the chamber, or in between the valve seats, replacing the seats will repair them. I wouldn't trust too many folks with cast iron repairs. Dover Cylinder Head in Atlanta is one I would trust, though.

Oh and the port sizes on the Magnums are same as the LA 340/360. That's even yet another benefit.....for upgrading a teen anyway.