1987 head different than 1990

[bthoms]

Crap, I just found out that the 87 head I'm trying to put on the 90 block doesn't quite work. The head studs are smaller diameter on the 87 and the head near the exhaust mani is thinner and the stud holes in the 87 block are deeper, in order to receive the same length studs.

I suppose I could drill out the holes on the 87 head, and make some thick bushings for the exhaust mani area holes, or just get shorter studs. I don't have a any machining tools, so drilling would take some time.

Thoughts?

[bthoms]

I went through an old post I had on here about the used 1987 engine. I saw several posts that suggested that the 87 might be a 6.9. One of the posts showed a picture of of where the block is stamped, by the d-side of the oil filler housing, and the first number in the series will either be a 6.9 or a 7.3. So I just now went out to the old block and scraped away the gunk and sure enough,

It's a 6.9, crap.

All this time I thought I had a 7.3. I suppose a bunch of the peripheral parts are interchangeable. Can't believe I didn't check that number before.

Maybe I'm best off looking for another 7.3 head.

[LMJD]

6.9 head bolts are 7/16", 7.3 are 1/2".

[bthoms]

Yeah, I figured that out. What do you think about the pre-chamber size and valves? and what about the fact that one side has a 7.3 head and the other side would have 6.9 head? Seems like things might be a bit unbalanced.

Thanks

[chuckster57]

IIRC, the 6.9 precups are smaller. I don't know about the valves, but it seems like you would be better off with a matched set of heads.

[bthoms]

Agreed. Just doesn't seem right. thanks

Any good reman places for heads anyone?

[typefour]

you could bring it to me. and I do have some good 7.3 heads laying around.