In my opinion, all years 440 blocks are just fine unless you have a blower, 3-stages of nitrous, etc. with more than maybe 600-650 horsepower. Also, 74+ blocks use a larger lip on the center main bearing which is preferred, but not required.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"