I ran a streetable version of a 415" small block in one of my old 1t 4x4s for a number of years,never had a problem with the 400 block.
I did use a 2 bolt main block with main studs since everybody told me they were stronger than the 4 bolt version.
my combination was in the 425-450 hp range backed up by a truck 4speed and 4.56s and locker in the rear and 4.55s and a limited slip in the front,would take my 8,000lb 1t 4x4 dump truck and bend it like a pretzel at will!
a buddy of mine is still running that same motor in his heavy ass 64 impala wagon,ill find out what his 1/8mile times are
