can anyone make a custom adapter

I need a 6x8 hole for a 8" opening.I have 2 8" speakers in the rear of my car deck and I want to put 6x8's there but i'm not good with fabricating.I just need a set of rings and I will pay with paypal accountthanks

Wow, if I had 8" openings in the rear deck a set of 8W7's would be in them... what vehicle are you driving?Support the12volt.com

It would not be really considered fabricating.  Remove the 8 inch woofer, place it upside down on a piece of 1/4 inch MDF, trace the outside of the woofer.  The 6 x 8 speaker should have a template with it, place that in the middle of the traced circle of the woofer and mark it.  Drill a hole in the middle of the 6 x 8 hole.  Using a jig saw cut the 6 x 8 hole out.  Now cut the 8 inch hole.  If you are not comfortable using the saw, draw it and I am sure you know someone that can do that for you.

Would 1/4 MDF stand up to regular driving/heat/moisture? I would be afraid MDF that thin wouldn't last long.

I live in Louisiana, here it is not called moisture, it is Humidity. We have tons of that, we will not mount an overhead in MDF (for other reasons) but we use it for speaker adapters and spacers all day. I have never seen or heard of a problem using it. But if he feels better, some 1/4 inch plywood will work just as well.