DIFFERENCES BETWEEN 289 AND 302 ??

hi,
to make a long story short,my g/f's dad has a 289,not sure of the year yet,just thought about this today. but i have a late 80 roller 302,and i have already bought pistons and rods for it,and was just wondering weather i could use my pistons and rods in his 289 block? i have tried to check stuff out through summit,and from what i can tell,i can,the pistons seem to have the same parts numbers for 289,and 302,im kinda stumpped on the rods,because if im not mistaken they had 3 different rod lengths there,and they was 5.090,5.155,and 5.400.now im sure they are for stroking the 289.just not sure what options i have,if someone could help me out that would be great.
i have speedpro forged pistons 4.030.and eagle forged i beam rods 5.090.if i can use it in the 289,what crank would be the best? i would like to keep low compression if possible,because i want to run boost. and is there anything i need to keep and eye on or should i be just fine? i had my 302 machined before i knew they was weak blocks. and this is just a way of helping me build some good horsepower and not have to worry about the block cracking down the middle. thanks for all your time and input.
 
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A 289 block isn't *THAT* much stronger than a 5.0L block. The 289 block will take some fancy machine work to take the 1-pc rear main seal 5.0 crank and it doesn't have the hole in the side of the block for a dipstick either.

I wouldn't mess with the 289, I'd just finish rebuilding the 5.0.
 
i was meaning maybe using the 289 crank instead,and using my rods and pisonts. i dont know if that would work or not. im just checking my options. and i have to buy a crank yet,and oil pan. pretty much all i have is the pistons,rods,and the block,i need most everything else. thanks
 
i was meaning maybe using the 289 crank instead,and using my rods and pisonts. i dont know if that would work or not. im just checking my options. and i have to buy a crank yet,and oil pan. pretty much all i have is the pistons,rods,and the block,i need most everything else. thanks
You need 5.155" rods with a 289 crank and 5.090" rods with a 302 crank. 5.400" are stroker rods.

Plus, you'd have to have the 289 crank machined if you wanted to fit it into a 1pc rear main 5.0 block
 
i think we are getting a little confused,sorry. i am meaning using my pistons,and rods and a 289 crank in a 289 block . i have the higher comp. pistons,and with the shorter rod,i should have low compression,what do you think??? if they would even work together i dont know. thanks .
 
You could BUT, the shorter rods would reduce your compression ratio and you would lose power, unless your goal is to reduce compression??? TBO, you can do a whole lot with these little motors, I put chevy 5.7 rods in a 289 to make a long rod motor to see for myself if it had any advantages. It is an age old dispute that seems to never get settled.
 
yea,that is kinda what im looking for. i would like to lower my compression some. as it is right now,with the heads and all,im looking aroud 9.5.1-10.0.1. compression. how much do you think my compression would be with the rod so much shorter? all the heads i like play around 58cc-60cc.and how much power is a 289 good for,meaning the 302 is good till around 500 ish,and then its just a matter of time before it breaks. how about the 289?? thanks alot guys.
 
Just my opinion but that is perfect already. And if your reasoning is boost then you really need a little stronger setup if the compression matters for the levels that require it.