STREETS.
the 350 in a blazer...what i was referring to was his comment about the ECM...Electronic Control Module for you points guys. Since the 78 didn't have one, and the S10 had a 4 or V6 he can't be using that one (or he may be....a problem right there!), what is he running? He says engine needs more fuel...well, that is the job of the ECM, isn't it? (need pictures? charts? graphs?)

"My MAP sensor is telling the ECM it needs more fuel" - not likley.
MAP - manifold absolute pressure sensor. It reads vacuum and load on engine. O2 sensor read rich/lean and THAT might tell the computer that more fuel is needed.

What he probably has is an out of range on the map sensor due to lopey idle or low vacuum....

been a while since i used a vac guage...correct me if i'm wonrg (i know you might hesitate, but don't) 18 is about max, 14 is normal and under 11 is low? I don't get into anything where ti sis an issue. On synchromizing bike carbs, vac between cyclinders matters, not absolute vac reading.