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I've got a mystery smallblock with the serial number: D4DE-6015-AA. Can someone help me decode this puppy? Thanks.
 

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I believe they stopped making the 289 in 67. The number you gave has a D4 in it meaning 74.
 

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Thanks. So I guess then that I can rest assured my engine is a 302, made in '74, not a 289?
 

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That shouldn't be a 289 with a D4 code on it. By the way, they quit making the 289 in 1968, not 1967.
 

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Yes, I think it changed during the year. The 289s from the first half of the year are a nice arrangement because the cylinder walls were extended for the new 3 inch stroke, which lead to greater piston skirt stability with the 289 crank.

<font size=-1>[ This Message was edited by: Flatspot on 4/4/02 9:30am ]</font>
 

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In 1968 it was hard to tell what you'd end up with. They were using up all the leftover 289 parts, and coming out with the new 302 at the same time. I've seen factory 302 blocks with 289 internals and 289 blocks with 302 internals.

The ONLY fundamental difference between 289's and 302's are the cranks and rods. The blocks, and even the pistons are the same.

I don't buy the line about 289's and 302's having different length cylinder walls. The ONLY person who's ever measured and come up with ANY difference, measured one 289 block and indicated it's cylinder walls came up less than 1/16" inch shorter than a 302 he had. Factory tolerances and decking can account for that difference. Anyhow, any difference is not significant. They are all around 5 1/8".

Good Luck!
 

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I have also read that the 289 pistons won't work in a 302 because the crank counterweights hit the skirt and pin boss,(remember the 289 has longer rods).I don't know if this is true or not but the old Ford Performance book goes into quite a bit of detail about what pistons you can use and how you can mill .200 off the bottom of the 289 pistons to use with the 302 crank so there must be some truth to it.And yes by 68 the people were buying the 390 instead of the 289 hi-po and the 302 replaced the plain 289 so that was the end of it.
 

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I have also read that the 289 pistons won't work in a 302 because the crank counterweights hit the skirts
Well, the 302 rod is roughly 1/16" (0.065") shorter than the 289 unit. This was done because extra 1/8" stroke gave the crank 1/16" more throw. This allowed the 302 to use pistons with the same compression height as the old 289.

I don't know if they changed the skirts back then, but otherwise, the pistons are identical. All modern replacement pistons will work in both 289 and 302 engines.

Good Luck!

_________________
Mike Burch, 66 mustang real street
302 4-speed 289 heads, 10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367


<font size=-1>[ This Message was edited by: n2omike on 4/4/02 11:11am ]</font>
 

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Thanks for the info Mike the book is great but its getting a little dated.I wondered if the new aftermarket pistions would be interchangeable.I had to chuckle when I came to the section on the 351W.It basically says not to bother building one as a race motor,as the 351C has much more aftermarket parts available for it and that for the price you could build a couple of clevelands that would run circles around it.Its amazing what the aftermarket can do to change things!
 

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The D4DE is a 74 302 block. I have on too. I also have the riginal 289 in the 68 Fairlane. They used them up until they were all gone, midway through 68, then went to the 302.

Rick
 

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by the way, depending on the build date that's stamped into the block, I think the '74-'76 blocks were .030" taller than the pre-'74 and post-'76 blocks. I had one of them, and couldnt figure out why the pistons were .050" in the hole.
 

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Mike -

Rather than rely on my sample of 4 blocks, or my machine shop guy's sample of 400 (which both say there is a difference in cylinder skirt length between the 289 and 302 blocks), I blew the dust off of some of the books to check to make sure we weren't nuts:

"Casting number: C8OE-A ... Other information: extended cylinder skirts, 302 in valley"
George Reid, Ford Performance Parts Interchange, p. 24

"While this [the 302] seems to be only a stroked 289, additional changes were made. The main one was in the block casting, where the bottoms of the cylinders were extended to provide additional piston support at Bottom Dead Center."
Isaac Martin, Ford Windsor Small-Block Performance, p.14

"The 302 block is also slightly different from a 289, the cylinder bores extend a little further at the bottom to provide a bit more support for the pistons at the bottom of the stroke."
Pat Ganahl, Ford Performance, p.23

Either this is the best entrenched urban legend in Ford engine-building, or there's something to it.
 

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check this out,I have a 302 that had 289 rods in it. Talk about close tolerance,the pistons were so close to the heads that there is a perfect,I mean perfect,like you taped it off and painted it,print of the combustion chamber on the piston. Not one speck of anything outside the lines.
 
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