ok to start with the prob...my car runs fine and all until i hit wot and at about 5500 and up the the car is stumblin alot till it shifts and then run fine again.....as for the car it has a new 383 stroker in it with lt's/58mm tb/30lb.inj/stock maf/and custom tuned comp...prior to this prob the opti was changed because it again was running great but then hit about 5800 and died completely and wouldnt get a good spark or crank right so we changed the opti and all was good...also no codes/good new nkg 55 titaniums.good coil and icm....i'm thinkin the pump is starvin and i need a bigger one but not sure yet any help would be great here

 

What valve springs? Sounds like valve float or bounce.
Check fuel pressure and see if it's the pump.