By request, here is a short article on clearancing a block for a stroker crank. I have done this for a 350 -> 383 and for a 454 -> 496. The same principles apply, and the most important one is, don't hit the water jacket...

First, 3 cuts were made for each cylinder with the block resting on the top intake manifold surface. In this picture, you can see the oil pan rail cuts (1st cut) and 3 rod clearance notches (2nd cuts) the 3rd cut from this position is shown later. Here the endmill (1.000") is in position to cut the 4th rod notch.

This is the oil pan rail cut. It is not necessary to clean it of across the whole width, but it takes no more time and 'looks nice'

Another shot of the oil pan rail cut, and also a 'before' shot of the cam tunnel area.

2nd cut, cylinder wall rod clearance cut. This cut is easy to make, it is exactly 1 connecting rod (big end) width offset from the cylinder centerline because it is a clearance cut for the rod opposite this cylinder bore. Once you figure out where one of these cuts goes, the remaining 3 cuts are offset by the bore spacing. I don't believe the water jacket is thin in this area, but you shouldn't have to go back further than the oil pan clearancing amount.

This is the first part of the cam tunnel cut. It is done with the deck surface down. The left edge is lined up with the cylinder wall rod cuts, and is made to clear the rod bolts. The reason the cut extends to the right is to clear the crank counterweights.

Two more cuts, each made while the block was on the same side deck surface. You can see how deep we made this cut without hitting the water jacket. I wouldn't go more than .250, and of course as little as needed. You can also see the 3rd cut, which is done with the block back on the intake manifold surface. It is the notch that looks like it lines up with the lifter bore. This cut is for the top side of the big end of the connecting rod.

You can probably make the oil pan cut before you start assembling the engine, just cut it back almost flush with the block. There is no danger of hitting the water jacket (that I know of.) You can also make the 2nd cut at that time, just edge find off the main bearing saddles and move over the right amount, as measured on the crank. Another way to get the right location for the 2nd cut is to center the cutter on the opposite cylinder bank, then move back over to the bank you are cutting. Don't do the cam tunnel cut, even though it is done with the block in this positon, until you have done the other cam tunnel cut, and you have test fit the rotating assembly to see exactly where more metal needs to be removed. I'm sure a lot of this can be done with a grinder, but there is a definate benefit to taking the time to do it on the mill. For one, once you are in the right positon, you can make uniform cuts for all the cylinders without much work. And the mill is much quieter than a grinder.

Thats a good post. I learned don't hit a water jacket the hard way. I put a pea size hole into the #7 I believe right above the pan rail. My builder and I decided instead of welding it up (we already had done all the honing/boring) it'd be worth trying to use that steel puddy and then doing a street block fill behind that up to the first freeze plug. We'll see if it lasts.

Great post. Much needed info. thanks