I was talking to somebody about torquing the heads and he said that if the studs in the valley are torqued last and not like the book says that there is less likely to be a water leak into the valley. What do you all think about this?

Which Hemi motor?
If first gen Firepower or 426 Hemi probably not an issue, I've built and race both types using the factory recommendations on torque and tightening procedures and never heard anyone say that about the 426 Hemi motors
If it is a gen 3, no help from me due to me not know anything about them, sorry.

You can imagine what I think about it. I guess your "somebody" heard that on the internet? Or just made it up himself? By the way, have you ever heard of a 426 Hemi leaking water into the valley? Is your "somebody" like, Maurice Petty, Jake King, Keith Black? I'm always looking for new knowledge. I think you could, and I have seen, Hemi heads bolted on in any way possible and they won't leak. Why not just do it right? You have the time.

My engine leaks into the valley and a local racer said that is how he does it.

I've never heard of that. Also don't understand the reasoning behind it. What do you have for block/heads/gaskets?

What kind of hemi is this? Block and heads Iron or aluminum. What head gaskets? As said this is not a known problem.

Alum block that is crap with Stage V heads. It did it with both a Cometic and Fel Pro 1106 performance gasket. I don't really trust the guy that said this, so I was just asking. I think that I might know the cause, but that would mean the block is trash. I'm kinda grasping at straws.

i had a customer who brought me a new Mega 4.190 rough bore block to assemble blown pump gas stroker motor for his new street car, he did not want it align hone or deck so I did as he ask. put in a set of new rods, pistons and 4.15 stroked Mopar brand crankshaft, Stage V aluminum heads with a early Weiand blower manifold and a Littlefield 10:71 blower with a set of "Carb Shop" pump gas Dominator carbs. That motor leak water out of both cylinder heads at the ends at the corners of the block
It was the block deck surface being too rough allowing water to leak around the cylinders under the gasket and the block
Took it apart and had it decked and that fix it
That motor only made 927 HP at 7300 RPM with 7.5 lbs. boost on CA pump swill in 2002, it was 12% under driven with the timing set at 33 BTDC. We swapped the pulleys to make it have 13% over drive, retarded the timing to 25 BTDC, put in some 116 octane Union 76 race gas and some colder spark plugs and it made 1024 HP at 6500 RPM with 12.5 lbs of boost before it went into detonation and started missing a bunch.
Bottom line is all things in any Hemi motor need to be correct for them for them to run right and make some decent power.

Take block and heads to a good machinist and make sure block is square with good surface, and that heads same/ level.

There you go. The way you started this post one would think stock Hemi. As said you had better get the deck and head surfaces checked and corrected. Then depending on gaskets used there may be some other sealing techniques needed for proper sealing. Head torque is most likely not the issue here.