I was trying to figure out how to drill the 1/4" holes for the plenum attachment to the cylinder head.

My solution was to get some 1/8" diameter neodymium magnets, wrap one in tape until it's a good fit in the hole, position the plenum, locate the hole now with another magnet.

Placing a piece of tape under the magnet and tapping it with a mallet left a mark at the exact centre of the hole to drill a #12 pilot hole and fix it with a #10 cleco.

I had to buy a pack of 40 magnets ($10 at Home Depot) so can spare a few if anyone wants to try the same.IMG_0253.JPGIMG_0254.JPG