A few weeks ago I swapped my Crossfire/X-Ram setup for a 4bbl holley pro-jection TB. I am very happy to report that I have almost got the 7747 tuning finished and its working VERY well!
I was prepared to build additional injector drivers, but in the rush to get it started, I initially ran the injectors in series pairs, like Howell and I think Turbo City used to do. I know grumpy will yell at me for doing that ;-) LOL... It idles better than before and revs cleanly to my 5800 rpm shiftpoint and feels at least as stong as when it ran 12.8's with the crossfire/x-ram setup. I will finish the tune and take it back to the track within the month for testing. I could never have done it without my WBO2, that tool is the most useful thing in my tuning toolbox ;-)
Here is an early pic before I had the throttle, cruise and TV cables worked out..

 

It'll run with half the voltage going to the injectors, it just needs to be tuned like you're doing. The only thing I would be a little worried about is getting a low idle to be stable with a warm engine (low pusle width). Other than that, keeping the revs under 6000rpm seems to also keep the injectors away from flaky.
Those are the old problimatic holley injectors you have. Please let me know how they work out for you and what fuel pressure are you running?
Good luck and I'm looking forward to your track results. Please do (if you can) post a datalog of the 1/4 mile run.

 

GDay Jon,
Yeah, i understand the 1/2 voltage prob, but it *seems* to be working out ok in this case. I kept the FP at minimum (12psi) for that reason.
They are the crap injectors, but they are working fine for me just now. I must admit that the spray pattern they produce is not as nice as the GM injectors.
I got the TB pretty cheap, and am prepared to upgrade the pod if required at a later date.
I don't know the PW at idle, but it idles smoother than it did with the previous induction setup.
I will soon be swapping to a 16168625 PCM and using datamaster, so that will give some more useful info than I currently have with the 7747 and winaldl.

 

Cool beans.
What size are the injectors?
You can put pulsewidth in the ALDL datastream. Just datalog with winaldl and use excel to do the calculations on the raw data. You can spit out just about anything through the aldl since the lookups are stored on the eprom. If you're interested I've made it really easy by writing an ecu file for Tunerpro to do just that. Before I got lockers I used it to output Final SA in place of the otherwise useless Eprom ID. I also didn't care for battery voltage so I made that the desired AFR. That way I could see what my choke, open loop, closed loop, and highway mode were actually doing .

 

Yep, I've done that before using your .ecu file ;-) Its fine for idle, but the slow datastream of the 7747 makes it impractical for WOT PW logging..
I just wanted to see if i could get it to run with the 7747 as I am comfortable tuning that ecm. If it worked out (and it has!!!) I then planned to swap to the '8625, knowing that if i couldn't get it to work then it was my ability tuning that PCM, not the holley's fault. Thats why i didn't want to swap both at the same time ;-)

Maybe if i get time tomorrow I'll patch the 7747 datastream, just to see what the pw at idle is.. else i'll just wait till i'm running datamaster with the '8625.

Injectors are rated by holley at 86pph@21psi or 60pph at 12psi. I have them at 12, so its like having 2 x 120pph as far as the 7747 knows.. PE was way rich initially, but I easily tuned it back to 12.x:1.

 

Ok, I was thinking about doing this as well, but using the holley 700cfm 4bbl. Please tell me what your chip is all about and you wired the sensors from GM to Holley. I am trying not to use the holley ecm. I am putting this in my 87 Chevy truck

 

If you intend to use only the 700cfm TB, I'd be tempted to just use the 2" 2bbl at 670cfm. That would be a lot easier.
But, to answer your question, the TPS plugged right in, The IAC uses a flat 4 pin weatherpack connector, not the square one like the GM TBI. I bought some watherpack connectors and made a short adaptor harness for this so I didn't have to cut up my cars harness.
And the 4 injectors are wired in 2 series pairs. Technically this is not the correct way to do it, but for me its working very well. I did another tuning run this morning to correct a lean spike on the gearshift and also to fix a stutter when given 100% throttle from a standstill. It's pretty much spot on now ;-)
It would be handy to have a bit of tuning experience with your chosen ecm before attempting this swap.

 

That was my first choice, but it won't support my HP needs. The 700 is good from 200-400hp with four 65 lb injectors. I am going to try the holley system in full first and see what is it made of, then go from there in one of several directions. Eventually I will run a multiport fuel rail injection on my vortec intake using Megasquirt to controll the 8 injectors and timing