jlinde Posted December 17, 2009 Report Share Posted December 17, 2009 I have found a Northstar which I just want to have as a spare but there is one thing that seems very odd: the block and heads look just like a 93-94 and the intake is newer. The heads have the castings for exhaust gases to mix with the intake gases as the 93-94 head but the holes that normally are drilled to accept exhaust gases from EGR-valve are not drilled. The intake does not have any provision for exhaust gases which means that the EGR valve just sits there without any possibility to do anything. These heads have different casting numbers compared to 93-94. This engine is not directly taken out of a car so somebody could have mixed things. It is helicoiled so I have to do the time sert or big sert. I think I can just drill the heads to get them to fit a 93-94. /Jan L Link to comment Share on other sites More sharing options...
Cadillac Jim Posted December 17, 2009 Report Share Posted December 17, 2009 The 1993-1994 Northstar has different heads from the 1995-1999 Northstar because the EGR was changed completely. In teh 1993-1994 heads the EGR passages were internal. The "mouse holes" or EGR passages under the intake manifold were left in the 1995-1999 heads but were blocked off, as you observe. Use 1995-1999 heads on a 1993-1995 Northstar at your own risk, but you might try drilling out the passages to match the older head if you can't get a head that is an exact fit. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
jlinde Posted December 17, 2009 Author Report Share Posted December 17, 2009 The 1993-1994 Northstar has different heads from the 1995-1999 Northstar because the EGR was changed completely. In teh 1993-1994 heads the EGR passages were internal. The "mouse holes" or EGR passages under the intake manifold were left in the 1995-1999 heads but were blocked off, as you observe. Use 1995-1999 heads on a 1993-1995 Northstar at your own risk, but you might try drilling out the passages to match the older head if you can't get a head that is an exact fit. Thank you for the info - I have a set of bad (scored cam bearings) 94 heads to compare with so I hope there is no other difficult difference between them. To drill those newer heads does not seem difficult. /Jan L Link to comment Share on other sites More sharing options...
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