... let it out.
Many others have done this mod and I've been contemplating it for the last 50,000 miles on the van. Finally time.
I bought the large louvers from RunCool like eBadger used. http://www.hoodlouvers.com/
. After ordering, I had second thoughts and tried to change order to medium, but too late. Now that they are on, I'm glad I went with large. I think Chris at UJOINT uses medium when he installs.
First I removed the hood and worked from the underside to mark, remark, re-remark until I figured out where I wanted them.
Then I drilled holes from the underside to mark where all the turns were when I would cut.
Then I taped the hole outline on the top using the holes I drilled as corner markers.
Then a Dremel makes easy work of our fiberglass hoods.
.... and voila, you have big holes in your hood.
Next, lay the louvers on the hood top and measure, measure, re-measure, mark all the holes, erase all the marks, re-measure and finally re-re-remeasure again. Re-mark the holes and drill a lot.
Then after inserting lots of rivets, you are done.
Re-install the hood and done!
eBadger mounted his as an angle to make best use of area of the unreinforced cut out area under the hood (and works well with his hood graphics), but I elected to mount mine straight.
Next trip up is hauling small trailer over the Sierra to Black Rock City. Will see if it helps keep temps down some.