88 TII
Currently, I have a 5k mile streetported motor, 3" TID, removed extra throttle plates, and rewired walbro 255
I am soon to install a 3" exhaust along with a FCD.

I am curious as to what injectors I should use? I have 4 spare 550's laying around that I want to send to RC to have bored. I can either get two of them bored to 850's for the secondaries and leave the primaries as is. Or, I can bore all of them and put larger ones in both primaries and secondaries...maybe 650/750 i guess. Anyways, has anyone run larger primaries with the stock computer and made them work? AND, will 850 be too large for the secondaries? 720's would just be enough so i thought 850's would give me a little room for improvement.

OK, lay it on me. What should I do?

 

larger injectors of any kind on a stock ecu with no piggyback will cause it to run rich.

 

well, i'm not so worried about it running rich. it's better than lean. the main question is, will my car run at all with slightly larger injectors in the primaries. like, what kind of problems will i have to face by putting 650s or 680's in the primary holes? if i can put larger inj. in the primaries, my secondaries don't have to be so large.

At WOT, there is no doubt that I will be running rich with 550/850. 550/720 should be perfect but that doesn't leave room for improvement. I don't want to have just enough in case i end up with more power than estimated. most have said that they put 720's in the secondaries without any noticable problems. i want to know if 850's is going too far.