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The difference between 289 and 302 block?

13858 Views 7 Replies 5 Participants Last post by  Shnate
The guy at my local machine shop says that the 289 and 302 are the same block with the same bore but just a different stroke. Is this correct? I have a 289 block that i'm going to get machined and i have a 302 crank, cam and heads with a bigger valve job done on them. What do you guys think?
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Yep, that's the deal - a 302 is a stroked 289.
For the most part, yes the same. The '73-76' 302's have a tall deck height meaning only 8:1 compression ratio with the pistons used. There are other little differences.
It will work fine...a 331/347 stroker kit is really the way to go, huge power out of a small block
I could be wrong but I think the rods are different too
I dont believe a 302 will work in a 289 with 289 rods
I would make sure first
Yep, the rods are different due to the different stroke. The Boss 302 does share the same rod length as the 289 but different design. One thing I happened to think about in the block differences is the length of the skirt in the block, some of the 289's are shorter than that of the 302 and might cause problems with a much longer stroke.
Thanks for all the replies, i'm fairly new to engine work and i was also wondering about the rods too. You guys nailed it :bigthumbsup So do you think the heads i have will still work just fine? This stuff was all in an engine which ran on a test stand for about 15 mins so i think it'll work. The guy had an engine built and then decided to go with super high performance stuff. I bought the parts from a guy I trust and he had the parts checked over by a machine shop. The heads i have have had some sort of valve job. I think the original size was 1.45 inches and they have been done to 1.75. I hope that gives me some more power.
Sorry, heads are 289 heads.
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