wierd noise on throttle

[dcZ71]

From about 50-65 if I give throttle input, I get this scratching kinda rough noise, sometimes its a pattern like chhhhhh-chhhhh-chhhhh. But only when touching the gas and only in this speed range. Im thinking its possibly just rear end noise?? l Anyone know what im talking about?

 

[454ss]

cracked flex plates can sometimes only be audible at certain rpms, its usualy pretty loud though. sometimes they sound like a knock too.