65 dart,Though the picture from speedway doesn't show the large aluminum plate/shield(Much like 805's homemade one) that may be it. You layer it with the fiber gaskets between each thin aluminum spacer. maybe a stack of 3-5 of each .
Yes you have to be careful as to not overtighten. Also any auto part store should carry the 4 hole dual bolt pattern fiber spacer that is about 3/8'' thick. I got mine from a Carquest store. That will help.
