Here, let me hold your hand and walk you through it. See, the afm b-31 is an anderson product...so click on that. Then you'll see a list of the products and since you want the b-31(which is a cam) click on the hi rev cams...you'll need to know if you have a 4.6 or 5.0. After doing that, you'll see a number with a funny sign in front of it..looks like this $.