Transmission problem!!!

Well about a month ago I got the 700 R-4 transmission rebuilt in my el camino. An the past few days i've noticed that if im going like 70 or so and stomp the gas the engine revs like in neutral. But all other gears shift great. If it matters it has a B&M shift kit. Thanks for any feedback!! :smokin:

kickdown cable isn't tight enough would be my guess.

Well turns out it was the overdrive. The guy didnt beef the overdrive up enough for the other parts he put on, but hey hes gonna fix it for free. Thanks for the input.