Quote:

I had my '99 360 block sonic checked before it was bored.... and they pretty much told me that with boost - 4.030 was really pushing it. All I know about them is what my machinist told me (for what it's worth) ... He thinks if anybody wants to go 4.220 on a Magnum block - they will have to install 8 sleeves.

Once again - I am NOT an expert - just a consumer that's passing along info second-hand.



The block the OP is referring to is a version of an R3 Block that takes all the magnum hardware.
http://www.moparsupercenter.com/mopar-5-2-318-magnum-race-block-pn-p5153579p5153579.html

As has been stated, it appears this block is for Push rod oiling only, and is basically set up to run the magnum stuff. It would be great if you are running a Hydraulic roller though. Your machinist isn't going to like you, and you won't be liking the bill you get for the bore and hone job!
If you are buying the block solely because it takes a 340 pan, there are spacers out there for $40 to fix that.

Alan Jones