Help with TBI conversion

[Opas69]

My sbc engine is 355 ci, 9.5 cr, melling MTC-1 278/288 .421/.444, 193 heads, stock tbi intake/throttle body, headers w 2 1/2" dual exhaust and 700r4 going in 69 Camaro daily driver(hopefully torquey). I will start with 7747 AMUR ecm with chip swap and harness from 1988 gmc van. I think I will be around 330 hp. Questions: # 1-I calculated fuel needs, what about using 80/90 lb/hr injectors around 18-20 psi?#2-What about initial startup with AMUR data in ecm? Possible tweaks?#3-Is WB O2 necessary for tuning?I am sure there will be more to follow.Thanks in advance, Steve

[Xnke]

I am assuming that you're using the complete wiring harness, computer, sensors and intake manifolds from the 88 van, and that the 88 van had a 350SBC in it to start with.

If so, then once you change the injector constant to match the injectors you decide to use, then the engine should start, run, and be somewhat close to drivable-you'll want more initial timing advance and less total advance, and probably a smidge more fuel through the midrange.

Assuming you are using two identical injectors, you need 150lb/hr total fuel flow to make 330HP. A pair of 75lb/hr injectors would be fine, or 80lb/hr injectors at their rated fuel pressure would also be just fine.

Yes, a wideband O2 sensor is a practical requirement for tuning any open loop areas of the maps-and will get you much closer much faster than using narrowband tuning. People will tell you otherwise-they've probably never tuned with one or tuned anything at all. A wideband will let you do the job so much faster and better that it's just not worth working without one. Spend 150-200$ on it and you'll never regret it. It's very useful for setting up carburators, too, although people will look at you funny when you say that until you've gone through theirs with one, and they see the difference in how it runs.

[Opas69]

New car build, just doing the hardware side of the tbi swap now. All the parts are from a 350ci GMC van. As I know very little about tuning I will dig deeper into that before startup. I will dig thru my Tunerpro to find/understand the injector constant and timing tables. I am sure more questions to follow. I will buy a WB O2 and possibly make room for disceet af gauge in dash as it is not complete either. THANKS FOR YOUR HELP.

[Opas69]

I am reading that I should use Lambda not AFR for tuning. Who has the most reliable package? I am working on dash and would like to incorporate gauge. And do I need it to log or just get help when I am tuning WOT? Steve