New member here, however, been reading and learning for years. This has been covered many times, but still not getting it right. I have a severe lean stumble when starting from a stop. Manual transmission. Both WBO2 gauges (laptop and stand-alone) go 17-18 to full lean and car falls on its face. I only need to just touch the gas pedal for RPM to increase. Maybe 2-3 TPS numbers and it revs to 1500-1700. I have changed everything in the AE section with little to no benefits in this off idle area. I enriched even to the point of very sluggish throttle response in neutral. Otherwise car runs extremely well in all other areas (after many hours of adjustments). 11s in the quarter spinning bad in first & second. I was running a Hilborn EFI 8 stack, but got tired of fumbling with the 8 individual air flow butterflies and it never sounded right. Additionally, no ports for IAC or PCV, but no stumble of idle. I'm now running a dual plenum with four runners each and two opposed 65mm throttle bodies. Very similar to an old Ferrari. Same 42 lb/hr injectors from Hilborn. Starts & runs well without touching gas. I also detuned my cam 10° on each intake & exhaust to get more vacuum. No help with stumble. MAP area at idle is 44ish. @ 1000 RPM. 410 cid Cleveland block, aluminum heads, roller roller, ect. Timing at idle is 22°. Max 35° by 3000. Cam is 252°-258° dur. @ .050" 638"-656" lift 114° LC. Is it possible my plenums are too big and have dead air? Still it's very herky jerky under 1800 RPM. I have had bigger cams with smaller engines, but nothing this severe. Any help greatly appreciated.