ok...89 E350 with the 351. The smog pump was going bad, the bearings were beginning to whine and i thought the thing would lock up any second. So i removed it, long with all the plumbing, from the pump to the aluminum tubes that connect to the exhaust manifold. The crossover pipe that is plumbed into the smog system that connects the two heads i capped, because i did not think it would be easy to plug whatever holes were there. The only connections to the vacume system i found were 2 vacume lines that connected to what i assume is the valving system where the line from the smog pump is seperated into the plumbing that goes to the heads and manifolds. And one vacume line that controlls a switch pumping air into the air filter housing. I plugged these three lines and plugged all holes. I think i removed pretty much all the smog system. There is no cat on the van either. My question is this. The performance is bad. I began with a stock van, cut the exaust and put in a flow master, performance was awsome, but the noise was too much in the van, so the exhaust shop put in a glasspack to help quiet it down, but the performance dropped. On a few long trips the van would suddenly randomly surge with power, ususlly up hills. Now that i have removed the smog equipment the surge is gone and i have low power. Any suggestions, i am going to try a new o2 sensor, but is there one that would work better in the van with no cat or smog stuff? Any other suggestions about the random surge of power? Also, in every ford i have ever driven the valves tap under power and its verry annoying. I call it the ford noise, unless i run premium fuel in a one ton van that ges like 6 MPG the valves tap relentlessly. Any way to stop this.

Sorry for being long winded, just want to give you all the info.

 

 

This question belongs in the 351W forum not the 351M forum. Ford quit making 351M/400 motors in 1982 and they never had O2 sensors on them.