Best year for a Northstar??

From 93 to 03 the head gaskets are pretty touchy. I don't think they were the whole problem though. You have an aluminum block, aluminum heads and steal head-bolts. I firmly believe that if you keep up with the cooling system maintenance and never let the engine overheat (I consider 240 and above overheating) the head gaskets will last forever. However, if you do overheat the engine, the aluminum and steal have different expansion rates when they heat up. The aluminum will expand more than the steal, putting a great deal of pulling force on the head bolt threads in the block. Once you've overheated once, the threads in the block are already weakened and it's only a matter of time before a leak develops. Unfortunately, there is no way to get away from these differing expansion rates. The only things that could be done were to rearrange the bolt pattern, make the threads slightly more coarse, and make the head bolts thread deeper to have a more secure hold in the block. I think the best years are actually anything that's 03 and newer; however there is a huge decline in the amount of bad HG's after 2000 simply from them rearranging the bolt pattern and changing the alloy in the block casting.

5 years ago when i bought my 98, the 94-96s were considered the 'bad years', and the 97-99 had only started having a few here and there w/bad HGs, and now everyone talks about the 97-99s being the 'bad years' because most aren't running 94-96s or if they are they've been repaired, and there is already talk of redesigned 2000+ having failures. Give it another 5 years and the 2000-2003 will be just as bad as the rest, maybe a little better, but don't expect much, these are all still die cast blocks, no matter the year, and they all still use unreinforced head bolt holes. There were porosity issues of these blocks, look at the threads where drilling the aluminum comes out like sand instead of chips. Realize head studs w/some serious thread pitch, Timeserts, or Norms Serts will probably be required due to the defficiencies of design. Lack of maintenance and age contribute to accelerating failures, but the design has been shown by numerous engineers and service technicians, and backyard mechanics on this board to have issues...

GM used to die cast LSx engines, until they found out it lead to porosity issues which was bad in engines used for race motors, so they switched to sand cast and have never looked back, but the N* didn't get that treatment, and IMO is the overrriding problem.