There are a few real engine guys on this site, and some of them sound like they do in fact know what they are talking about. There opinions should carry more weight than mine thats for sure, but here is another opinion.

I wanted to get away from the regular small block chevy for a couple of projects that I have under way. I have always found the 348/409 engines to have a cool look. These are both street cars first so the performance wasn't the number one thing. I found and purchased two 348 and one 409 engine for these cars. All three of these engines needed building, but they cleaned up at .030 or .060 so no problem. But in researching the 409 it was interesting to discover that many, many 409's are sleaved and I mean all eight cylinders. Many of these 409's are in drag and street cars and they seem to be providing very good performance as well as service.

Of course the 409 is a relatively rare block and if you want to save one you do what you have to do. Also if you check the all aluminum blocks have eight sleaves as well, and it for sure doesn't seem to hurt or bother them.

I don't have a clue weather it would be more cost efficent to find another block, but sleaving may not be such a bad deal after all. MAYBE!!

RS