The idea for a cone filter cover is great, and one I was going to suggest as well. Make it match up with common 3" or even 2.5" ABS sewage pipe (I.D. or O.D.) and you can sell it to ricers and rednecks alike. To go along with it: a snorkus adapter for the TBI on 2.8L troopers. Cadillac 4.2L engines from the early 1990's have something like this, but it's got an oval intake that's difficult for the DIY type to adapt to. Make one that goes "FROM TBI TO PVC" to go along with the cone filter cover, make them all waterproofable, and you've got yourself a product. BTW, as far as I can tell the TBI on isuzu has the same top neck as any chevy TBI product and also the same as most 2 and 4bbl carburetors found on chevy pickup trucks. So a significant market!