NS300l Northstar Thread Kit

[Cadillac Jim]

I just got the main page from both links.  Here's how to find the instruction sheets from the links on the main page.

Start with the main page, http://www.timesert.com

At the top of the page just below the flash animation, there are four navigation links, including "KITS & INSERTS".  Clicking those gets you drop-down menus, etc.  Select "Kits & INSERTS" -> "Manufacturer Kits" -> "General Motors"

Scroll down or search on the part numbers, 42385-500 for 1995-1999 (your engine), 42385-2000 for 2000-2003 (not needed today), or 42385-2030 (2004 and later, your kit).  Clock on the big blue link "INSTRUCTIONS" under the part number in the third column and you will be able to download a one-page PDF file for each kit.

I don't see much difference between the instructions sheets; they just tell you how to use the kit on each head bolt hole, and in general that doesn't change much between kits.  The big thing is that there is a caution at the beginning of the kit for 2004 and later that says to use a stop collar on the drill for the shallow holes, but there are no shallow holes in the kit for 1995-1999.  I would gather that there is no guarantee that the drills are exactly the same length, so I wouldn't use the kit for 2004+ for a 1995-1999 engine without talking to TimeSert and asking them.  There is a page you get to with the "INFORMATION" link at the top of every page that will get you a page with an information form link.

To save time and get to the point, the threads are different so the drills and taps will be different, so I would just get the right kit.

[Logan]

It could be done. But you would have to do some careful math. Do not use the markings on the drills...they appear to be in different spots....the stop collars are blocked by a dab of silicone....but that can be removed. 

Having both the J-42385-500 and J-42385-2030 thread kits sitting here.....unique photo op..

Both engines use M11 head bolts....so either step drill would work.

The 500 kit uses insert 11155. The 2030 kit uses insert 112030. Both are M11 and 30mm tall. The only difference is the 1.5 vs 2.0 thread pitch (which you can notice on the tools).

Picture shows....from top to bottom....500 step drill...2030 step drill....500 tap....2030 tap....500 driver....2030 driver.