'68 318 to carbed Magnum 5.2: Check my checklist
This is ancient, but I'm bumping my old build thread up here to add one caveat for those considering the roller-cam, TBI LA plan such as myself. This is something I did not realize until now, and that engine has been in the car for about 2 years already, and if you're building your motor with factory EFI in mind later on down the road, it may make a difference:
The TBI motors do not use a crank position sensor, so - unlike a purpose-built Magnum block, there are NO factory provisions on the back of the block for mounting a factory crank position sensor. This may be irrelevant for anyone planning to adapt their own tonewheel on the front of the crank, but for someone looking to get away with a stock setup, it's a deal-breaker.
It's something to keep in mind if you're considering a roller-cam LA like I did, but have future ideas of using EFI. If you do, stick with a Magnum-era block.
-Kurt