Re: [Amc-list] 4.0 head swap

["Glenn Ford" <gcmford@xxxxxxxxxxxxxxxxxxx>]

Hi, Fran

It's the first time I have seen you positive about the 87-90 258 blocks 
being wider. I hope you are right. Up until now, you sounded hopeful, as if 
uncertain.

I have been following various threads to determine if the 87-90 blocks would 
be wider as rumored. I had hoped, as I have all the parts, but still 
together in appropriate vehicles. With a little logic and the following 
links, I have made the following assumptions:

1. Unless someone has side by side and/or measured/compared, it is unlikely 
the same outer casting as the 4.0 litre, think about the fuel pump boss.

2. The 94 HO block shown, while not a good pic, quite apparently shows 
matching triangular passages, which, I assume would also be present in 87-up 
4.0 litre blocks. Also appears to be less curvy along that side.

3. Anyone who has got lucky with fitting an unplugged 4.0 head without 
leaks, should have a jar of (remember Bar's Leaks?) sealer handy, as it has 
to be close.

4. The switch to 1/2" head bolts in 87 probably coincided so as to not 
confuse inventory or assembly specs, not because it's the same block.

I have 2 87 Eagles and an 87 XJ Wagoneer, and the XJ is hopefully going to 
donate, if I live long enough. I think the epoxy trick is a viable way to 
go, anyway, or a stroker with the 4.0 block. If somebody can do a direct 
comparison with pictures and measurements, like bare Renix block and head, 
or a 87-90 258 block, verified, with wider measurement, then we could 
confirm or dispel the rumor. Looking at the pics below, I would guess not.

My garage still has no cement floor, or I would have had something apart 
already.


http://www.jeepnuts.com/tech/stroker.htm stroker article showing 94 HO motor 
and project pictures

http://www.jeepnuts.com/tech/stroker/bare_block_02.jpg HO motor, 4.0 litre

http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=277013 article 1 
shows the project pictures

http://www.off-road.com/jeep/tech/engine/40headconv/14.jpg close-up of 
block, same block as in article 2, before MPFI upgrade

http://www.geocities.com/035jeep/Moparpage1.html article 2 states year and 
mileage, likely original motor, 1990, last year of 258


Glenn Ford 

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