I thought that I had read here some time ago that the sleeves of the B18a blocks were (purportedly) weaker than those of a B18b. Is there any validity to this or is this a dream I may have had? I am thinking of getting another block to build up instead of re-machining my block that was already machined and rebuilt last winter.
Thanks in advance for impending commentary.

 

I have NEVER heard of this, and have seen the two motors opened before, and never noticed anything that looked weaker on the b18a1 version.

The b20s are a different case. They are the ones with the thinner sleeves.