I was curious about the differences between the two motors. I have a b18b in my car now, and down the road would like to get a motor sleeved and built up nicely but cant afford too much downtime, so i am planning on picking up another block to send away and get it sleeved and just have the block ready to put in.

so my question is, what are the differences, and will it just bolt straight up without any wiring or anything.

 

and also, what is recommended to be done to the ls head, if the bore is 84.5mm instead of the 81 after it is resleeved?

 

If you look 2 threads down, the exact same question is being asked.
https://honda-tech.com/zerothread?id=342467