I've got older SB manifolds and a complete custom exhaust, where should the O2 sensors be installed? I think I've heard to install them in a straight section (not near a curve), but how close to the manifold? If it isn't close enough, will they get hot enough or will the readings be off? Or is it not that critical?

 

From what i understand they should be within 12" of the head somewhere.. expecially if they are single wire non heated ones.. the 3 wire heated allows you to get them down in the collectors on headers as the hot wire will keep the sensor hot enough to get accuracte air/fuel ratio numbers for the ecm.. velocity of the exhaust probably does factor in but i think the operating temp is paramount over flow concerns.. course you didnt hear it from me..

 

Ok, do you have any pictures of your LT1 swap?