ok here is some backround. started with a 305 tbi, swapped to a 350 kept the tbi. right now i am running the 350 with the 305 injectors and computer. also switched to a single plane manifold and a luinati cam (458 lift, 218 dur) with stock springs, timing at 8* btdc

ok when i drive it normal it is fine no problems. as soon as i floor it and it reaches 3000 rpm it starts missing bad. almost like valve float. i just installed an air/fuel ratio gauge and at idle it reads rich. when i floor it it goes completely lean...

am i just not getting enough fuel? or is it because of my valve springs?

any ideas or opinions would help me out a lot. i really want to get this thing running good. thanks in advance. -jon

 

I would guess the valve springs. Know how many miles are on them?
But also the fact you're using 305 injectors and computer, with no tuning, and a single plane manifold, aftermarket cam, etc. If it's going lean (how lean?), then it's probably a lean misfire, which is pretty bad.
What heads are on the 350? Like is this a pretty hot engine?