Hello folks. Been running into this issue since before and after the engine swap. So I'm thinking of either two issues, whether its the transmission that's slipping or my throttle body failing to give enough fuel (same crappy TB from my old 305 but with 350 injectors).

So heres the issue: (also providing video with sound below so please listen to it to understand and hopefully help me)

At full throttle, certain times after around 70 or 80 depending on the RPMs, the car will instantly jerk and sound like its instantly going red lineing and I lose power. Its sorta hard to explain so heres the video. I accidently let off but when I threw back down on the throttle the sound emerges. It only does it at full throttle pedal to the floor at high speeds.

https://www.youtube.com/watch?v=4mHS...ature=youtu.be

 

Its downshifting?