Ok long story on how the engine swap began. The problem is I got a deal on a low mileage 4.3 out of a 2000 2wd Blazer to put in my 2001 4wd Blazer. So everyone is thinking... Won't work because the knock sensors are different. My question is can i just switch the bolt that hold the 2 wire knock sensor in to a larger one same threads as the 2000 1 wire knock sensor thread?

I Just took the 2 knock sensors to the Recycler that i bought the engine from. He said I can either use the old 1 wire model with the red wire to the top and the blue wire grounded around the thread or bring the engine back and swap it for a 2001 model he has ready to go with higher mileage.

 

I just did this earlier this week. All you need to do is drill out the hole and tap it for the older/bigger knock sensor. Dont remember what size drill but it is a 1/4 inch npt pipe thread tap.

took all of twenty mins. the taps are available at any parts store and say what size drill you need right on them

 

It is the correct size for the older knock sensor but my blazer takes the newer smaller 2 wire knock sensor. I am going to just return it for the higher mileage engine tomorrow. I just don't want to go hacking the wiring up.