The 351m400 have great potential, especially the 400, it was unfortunate for Ford that the first generation pollution controls where introduced at the same time. Dished pistons, two barrel carby, retarded cam timing, air pumps etc etc all combined to give the 351M400 the bad reputation as a smog boat anchor. All the usual improvements like pistons, carby,inlet manifold,good cam turns them into real good performers.The 400 has a 4.0" x 4.0" bore and stroke, now just top it off with a pair of Aussie cleveland head and go big block scrubs hunting.
Google 351m400 for a lot more information
Pete, one of the Aussie mob.
Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390