I put a 94 truck motor in my Barracuda, I had it stroked to 408 and internally balanced.
The problems I had were, none.
The motor mount ears are all there so you will not need different mounts. Just make sure they are correct for either a 273/318 or 340/360.
All I did was take the front end of my old 360 and put it on the Magnum. I ended up buying an aftermarket oilpan but that was not needed. You will also need a intake that will bolt up to the Magnum heads, or have the heads drilled for both, someone has a jig for doing this.
Just remember that the Magnums have a different balance then the LA's. So you will need a balancer and flexplate/flywheel for the Magnum or converter. Also I have heard that the pilot bearing is not milled, so if you have a manual tranny, you will need to address that.
I may have left out some of the differences, but the install was pretty straight forward. Just check everthing out ahead of time and be prepared, I forgot a few things and had to stop in the middle a couple of times. My problems were related to changing water pumps and power steering pumps. I ended up buying new brackets and pulleys, as the 69 pumps are shorter then the 70 up.
valentek
69 B5 408 FB
