Wix filters and 340 HP manifolds

S'cuder said
Figure a little less, as the base of the angle finder is sitting on the rim of the filter.

View attachment 1716099738

*Edit - the rim of the filter is worth two degrees. So about 16-17 degrees downward in my '68 Barracuda.

Thanks so much for everyone's input. Will use it gratefully. Thanks FABO.