I plan on building a 406 with either 5.7 or 6" rods, I have not decided which ones yet. I also havent decided if I'm gonna use I-beam or H-beam. This will be the first motor I've built where I will have clearance issues to deal with on the rotating assembly. Is there any paticular process thats works well for people to go by? By this I mean, bore block first? Grind first, then clean and bore? Cam bearings installed before or after grinding? Does the whole assembly have to go in and checked? Or can U do two pistons at a time?

i think you might want to check on some stroker-clearanced rods when you decide on the length,they might help save some clearance issues.personally,i like the i-beams better than h-beams because of the weight.scat and eagle both sell stroker-clearanced rods.i would have the cam bearings installed when you have the block bored because you'll want to install the cam at some time during trial assembly to make sure the rotating assembly doesn't hit the cam when you turn the crank.when you get the block home after the boring you need to clean out the cylinder bores with hot soapy water and a stiff nylon-bristle brush.immediately after (or during)the scrubbing blow the cylinder dry with a air hose and spray it down with wd-40 to prevent rusting,(especially the cylinder and lifter bores.)use paper towels and trans fluid to scrub the cylinder walls clean of all machining residue(small metal fragments)keep using fresh towels until you can wipe the cylinder walls and it comes out clean.also,make sure you clean the mains good before you install the bearings.there are a million nooks and crannies in a block(including the cam bore and oil galleries) metal can get into,so do a thorough job.i'll let someone else take your question from this point on for the clearance-grinding.

oh yeah,i'd have them clean the block before anything.

You will need to check the cam to rod clearance. Depending on what rod you use it can get real close.
The H beam & capswrew I beams will have more room at the cam.
The newer Scat 7/16 bolt I beam is cut real nice for cam clearance. It has more room then a stock 400 rod.
You don't want the cam bearings or any oil plugs in until you are done grinding so you can clean everything good when you are done.
There is a groove behind the cam bearings that is impossible to clean with the bearings in.
You may have to enlarge the notches at the bottom of the bores for bolt clearance & you can do it with the crank set in on two bearings & with one rod. Just put the rod on the crank & spin the crank while holding the rod in the approx center of the bore & check the clearance.
If it needs grinding, grind them all the same & then recheck them all. This way you can do all your own clearancing before any machine work is done.
You can do it afterwards but you won't have the advantage of the final cleaning your machine shop should do after boring, honing etc.
Obviously, you cannot check the cam clearance until the block is done & cam bearings are in along with the cam & crank, timing etc. & this is the part that gets a bit tricky as you want to grind the rods before balancing so you need to assemble the engine without rings & hopefully everything will clear.
If you go to a machine shop that does performance work they should know how much if any needs to come off the rods before assembly ;)
But you still need to recheck when you are assembling the engine.

When I'm doing custom fitting/clearancing such as you are getting ready to do, I use a "special" wrist pin for the job. Several years ago, I had my machinist reduce the diameter of an old wrist pin so that it is JUST a slip fit in the rod. This way I can test fit each piston/rod to its corrosponding cylinder. I then use a black magic marker to number the rod/piston after fitting/clearancing. That way, the machine shop puts the correct piston on its rod after balancing. ALLLLLLLLLLLL machine work must be done first (but don't have the pistons pressed on the rods), then bring the parts home for test fitting/clearancing, then take it all back to the machine shop for balancing and installing pistons on their rods.

Tom,
Good point on the rod for press fit stuff, I made one years ago for the same purpose.
I will agree that with anything over 3.75 stroke you need to be able to put the pistons in but we have done well over a 100 of the 383/400 engines over the years & never had a problem doing all the clearancing before any boring or deck work. We just put a couple of old main brgs. in without caps & check the rod & crank clearance.
Now with the 3.875/4" stuff that's a whole different ballgame :D

Read this is a good article and what you need to do.
http://www.chevytalk.org/threads/showflat.php?Cat=&Board=UBB64&Number=600471&Forum=UBB64&Words=Clearance&Match=Entire%20Phrase&Searchpage=5&Limit=25&Old=allposts&Main=599418&Search =true#Post600471 (http://www.chevytalk.org/threads/showflat.php?Cat=&Board=UBB64&Number=600471&Forum=UBB64&Words=Clearance&Match=Entire%20Phrase&Searchpage=5&Limit=25&Old=allposts&Main=599418&Search=true#Post600471)