85 vs. 86 vs. 87> engines

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This is what every 87-93 5.0 I have torn down looked like....
0306MM_ToHotpt203_z.jpg


See the "dished" area in the center of the piston? The ones in my 85 motor look the same as far as valve reliefs go but do not have the dish.
 
Well... I'll be the first to say that I'm stumped fellahs. Those pistons in the pic above look ALLOT like what I remember from the 85 and I cannot recall specifically what the 89 had in it (wasn't paying that much attention). Rick91GT may be able to help out a bit more with what's what. If it were me and I ever planned on forced induction, I'd go ahead with the 85 pistons you've got (regardless of what they look like) and maybe shave the heads to get your final compression ratio to where you want it to be. With the 85 pistons you have.... Are they shorter than the 87+ slugs you have lying around?
 
Daggar said:
Well... I'll be the first to say that I'm stumped fellahs. Those pistons in the pic above look ALLOT like what I remember from the 85 and I cannot recall specifically what the 89 had in it (wasn't paying that much attention). Rick91GT may be able to help out a bit more with what's what. If it were me and I ever planned on forced induction, I'd go ahead with the 85 pistons you've got (regardless of what they look like) and maybe shave the heads to get your final compression ratio to where you want it to be. With the 85 pistons you have.... Are they shorter than the 87+ slugs you have lying around?

What do you mean by shorter? Like further down in the hole or shorter skirts or what? Im definately going to use the 85 shortblock, including the pistons, one way or the other. Im basically just trying to figure out if the 85 shortblock and heads with the 87+ intake stuff is going to run lika an 87+ or more like the 86 motor. I wish I had an extra set of E7 heads lying around. The flat tops in the 85 block and the E7's would probably bump the compression a tad I imagine.
 
Daggar said:
Yeah like... how close does it come to being level with the deck at the top of the stroke? You've got my curiosity peaked now about what final compression might be with a set of E7s.
Not sure on that one. Looks pretty darn even with the deck but I could ren a feeler under a straitedge I suppose to find out for sure. I dont have any 87+ motors taken apart right now to compare it to though.