ls1 ls6
oh.......wow. there's a reason nobody has replied to this in over an hour and a half. look up JRP's handle. he's a mod. or find one of his many great sticky's, i think they are in the newbie/enthusiast section. MANY answers to be found there. also, judging by your post count/question asked, you might want to read those stickies for a few pointers as well. the search button is there for a reason, young grasshopper. 
keep asking questions like this w/o searching or reading the sticky threads that JRP has devoted many hours to, and you'll get flamed somethin wicked.
k, now to answer your question. the main difference between the ls1 block and the ls6 block, is that the ls6 block as different oil passages as well as big valley windows to allow better cooling. some people think b/c of this, the ls1 block is a little stronger(more material b/c of no windows). the heads are a whole different story. go read the threads for that. ls6 heads are totally different then ls1 heads, and much better. D-shaped port design, better flow numbers. vehicles that got ls6's out of the factory usually got bigger cams. as a matter of fact, one of jrp's threads has a cam spreadsheet originally comiled by jimmyblue that will tell you a bunch of different vendors' cam specs!! including various stock. manifold wise, ls6 outflows ls1 by a good bit. decent upgrade, very worthwhile.
theres your novel, now go get to readin jrp's sticky's. AND his guides listed in his sig. AND use the damn search button. we don't take too kindly around here to folks not usin the search button
keep asking questions like this w/o searching or reading the sticky threads that JRP has devoted many hours to, and you'll get flamed somethin wicked. k, now to answer your question. the main difference between the ls1 block and the ls6 block, is that the ls6 block as different oil passages as well as big valley windows to allow better cooling. some people think b/c of this, the ls1 block is a little stronger(more material b/c of no windows). the heads are a whole different story. go read the threads for that. ls6 heads are totally different then ls1 heads, and much better. D-shaped port design, better flow numbers. vehicles that got ls6's out of the factory usually got bigger cams. as a matter of fact, one of jrp's threads has a cam spreadsheet originally comiled by jimmyblue that will tell you a bunch of different vendors' cam specs!! including various stock. manifold wise, ls6 outflows ls1 by a good bit. decent upgrade, very worthwhile.
theres your novel, now go get to readin jrp's sticky's. AND his guides listed in his sig. AND use the damn search button. we don't take too kindly around here to folks not usin the search button
