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Northstar head confusion


jlinde

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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

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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.

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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

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