All I can say is over build everything, I expected a decent street motor with drag capabilities. I received a fire breathing 427sbc that destroys everything behind it. In less than 100 miles my 9" ford rear end is destroyed. Snapped studs off, repaired it and shattered an axle 30 miles later. If you are busy a 421 - 434 you better over build the driveshaft and rear end. So far my trans is holding up but I fear a monster mega as built 700r4 is in my future! Will be assembling a 35 spline rear end this winter to hold up to the engine and upgrade to 5/8" studs as moroso 1/2" snap off like a brittle twig, on street tires... Nexen n3000's hook up really well if you are interested. I should went with less motor and been satisfied with that😂