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I toasted my B21A1 in my 90 Lude last year and have had some problems locating a donor B21A1. I have found a number of B20A5 from the earlier gen Ludes. I am wondering if i can swap in the B20 straight up, or if there are some modifications that need to be done.
 

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Search? It will answer ALL of that!
 

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direct drop in swap. absolutely no differences between the outsides of the motors. just use your b21a1 intake and exhaust manifolds. b20 mani's wont work with the b21 harness.
 

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NO, the driverside mount is not the same, unbolt yours from the b21 block..the whole thing. use the b21 intake & ac mount as well.
If the B20A5 came with a fly/clutch & was in an 88-89, it won't fit your 90-91 trans. Downpipe hanger bolt holes on back of block are in a slightly different spot too, You might be able to get one in, but don't even really have to do that.
 

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lol, i'll reword that. the outsides of the motor are the same for anything that is important. drivers side mount is different, but just use all your b21a1 mounts and intake mani and exhaust mani and all brackets and flywheel from the b21 and everything will be a direct drop in.

there, thats what i meant lol. block and head are the same on the outside. the cosmetics bolted to each are a little different
 

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hey man im in the middel of that job right now i got a lude given to me with a fuckered motor and im swaping a b20a5 in to it its a 91 sr so it has a b21a1 just about to pull motor only cvs and mounts left
 
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