Just thought I'd post this since I'm sure some of you may go through this at some point:

I needed insulators for my 440s and finishline offered them for 8 bucks a pop. Holy ****? Anyway, I found these at rock auto as an alternative- they are 2.95 per injector, include the o-ring and top seal, and offer a significantly better quality seal at the manifold. (shitty cam photos attached). You can see the Finishline/Mazda insulator (pictured) has ribs and is not made of the same pliable material and covers less surface area. The part number is on the box for your reference..