I recently built a pretty stout 383. I was wondering how long my stock 700r4 would hold up to it. Im dialing in my tune and Im ready for the dragstrip. after doing a few test hits from a dig I found that at WOT shifting between 3rd and OD (at redline) the rpms surge hard to the point I'm scared of blowing my motor and I have to let out. It will shift eventually but half the hits I made, I let out early in fear of blowing the motor. Does this indicate its time to upgrade my tranny?

 

To make the 3-4 WOT shift you need to block the 4-3 on the TV plunger sleeve using two small Allen screws. Here is the link on how to do it. You do not need to remove the valve body to do this. The stock 700R4 will not last until you add some upgrades. If the transmission is still making shifts ok, you should add the Corvette servo and large boost valves at a minimum and the TransGo modified Performance Shift kit would be best here. Otherwise you will be going into this transmission quickly.

 

Couldn't have asked for a better reply on that. Much appreciated