HI its my first time posting here. I have a question I just bought a 1988 Ford F-250 4X4 and when I got it the cattilisstic convertor was off of it and the tubes coming down from enigine are just sitting down there and not one of them are plugged off I was woundering if I have to plug one off. It has a 351 in it. I just put new manifoilds on it and none of the tubes up there were pluged off either. Please help I'm hoping that that will bring up my gas milegage from 10 miles to a gallon.

 

I can't see it affecting miliage...but its probably illegal in your state...do ya'll have sstate inspections??

 

No Oregon doesn't have aninspection. I was once told thought if it isn't plugged off it would be telling the computer that it was still coldand the choke would be on.