243's, Manley crank, Eagle rods and CP pistons in my 5.3 here. I'm only pushing 10 lbs but I'm sure it could take a LOT more. As the others have said, don't bother messing with 241's.

 

Milled 317's are essentially 243's. Untill you figure what dish pistons your going to use, do not mill anything yet.

 

You need to stuff that thing with atleast 20, you are WAY over built for only 10 lbs

 

My buddy is running 10-12 on stock bottom end. U should up yours to like 15 at least dude

 

On mine ill probably go diamond or wiseco dished. What would u recommend milling 243s to? I'm actually on the hunt for some 243s now. I think I'm going to go 408 with mine if it get taken apart though If I'm going to build something I want it to be bauce. I joked with my cummins buddy earlier about going 408 with a twin turbo fed Maggie lol may even throw a procharger on to boot

 

I wouldn't have the 43's milled..

 

You need to figure out what compression ratio your shooting for and choose your piston and then decide how much you want to mill your heads if any at all.
Use this to figure your comp ratio
http://www.kb-silvolite.com/calc.php?action=comp
On the piston cc use negative numbers for dome and positive numbers for dish. For every .006 you mill off a head is 1 cc. Generally most aftermarket pistons are 0 deck.

 

I'm really going to start reading into this man..what would be a good ratio for 10-12 psi? I'm completely new to this. Also what would u recommend for 20psi for my buddy's application

 

If it were my build, I would get ahold of "Liljohn" off Yellowbullet.com and have him spec the cam, just tell him what you have planned to do, what size motor you plan to build, what size turbo, etc, etc, etc, and he will tell you what compression ratio to run for the cam that he will spec out for your build. His cams have made some serious power over others "spec" cams for boost. You will get so many answers off here on what compression ratio that you'll need to run.
Another thing, what turbo do you have? Do you know if it'll actually make 20lbs? What fuel and fuel system are you going to run, there's alot if things you'll need to handle the amount of power 20lbs of boost will make.

 

Yeah I was thinking the other day that his turbo is like a 66mm iirc and that's not going to get him to 20 so I'm thinking he has something else planned..possibly twins. It's a Garrett turbo. I was going to get pat guerra from guerra group to spec a cam out and all for him but ill look into liljohn