This may have been asked in the past,,,,,,,,but,why is it OK to drill air bleeds but a no-no on the jets.Having to change 8 at a time,being able to drill older smaller ones would make life good.

The problem with drilling jets is you may make the hole bigger but actually reduce the flow. If you look at the actual hole size of Holley jets you will find two size jets next to each other with the same size, but the length of the hole and whether it's chamfered or not will change the flow. Air isn't affected as much, although with the main air bleeds I usually won't drill, idle and intermediate air bleeds take a rather larger jump in size to effect a change so drilling isn't as much of an issue.

Never have or will drill jets but almost always drill my own bleeds and of course set screws.

How about the margin of error is much greater when you are dealing with 12 parts of air vs 1 part of fuel.




Joe

I use my drill indexed bits and measure the hole.Now I can increase the drill bit size to allow more fuel.If all 8 jets are drilled with the same bit,the orifices are the same,as would be another 8 jets to to a different orifice size.

Does this thought porocess make sence???

No it's simplistic to think that you can drill all 8 holes exactly the same. Swirl marks in the bores, entry and exit conditions all affect flow.

It's comic to see people who think they can do something better in their garage over a big company with the right machine tools and staff.

If one was worried about jets, one would buy high precision jets.

R.