Block mod cooling upgrade

[chargd72]

I'm building a supercharged 408 stroker.  I just did a partial fill on the block for some bottom end strength.  I bought my stroker kit from Mark at MRL Performance and he suggested I do a simple block modification to improve cooling.  Here is what he suggested. 

Tap the circled hole for 3/4 thread
Plug hole with pipe tap Pioneer #pp472
Drill 1/16" hole thru plug
Do this with both sides on the rear of the block

I'd like some opinions on how this will effect the cooling.  It sounds like it might restrict some flow through the heads.

[Challenger340]

Ok, I am confused ?    Why ?
What's the rationale for doing this as a "stand-alone" with no other modifications ?

Normally.... to recap "standard" coolant flow,
The Water Pump pushes coolant in the front of the block, where most of it down the deck front to rear is "restricted" by small head gasket holes(some flow) from going up into the Heads until it(The majority of coolant) reaches the rear of the Block(forced front to rear so as to go around and cool ALL the cylinders, including the rear cylinder).
where once the majority reaches the rear,
the majority is then promoted up into the Heads, and from the rear to front in the heads, back into the Intake/Thermostat for return.
The above is why the holes are smaller down the deck until the larger "one" at the rear ?
and,
also why as a general rule when installing Head Gaskets on North American domestic V-8's, and if unsure of Head Gasket orientation ? the "larger" coolant hole in the Head Gasket gets installed to the REAR.
Remember,
the coolant absorbs heat as it travels front to rear down the Block.

So in this case....
Plugging that rear hole, or restricting it, would promote more Flow UP into the Heads from the other smaller holes along the deck.
The only reason I can think of to plug/restrict the rear hole ?, relative to a Blower application, would be to address the greater exhaust heat load concentration on the Heads siamese exhaust ports(center 2 exhaust ports side X side), common on wedges(sbc/sbm/bbm).
Albeit,
IMO, I can't see the need on typical "street" type boost applications ? and I feel you would still be sacrificing rear cylinder longevity through excess heat, to fix what is IMO a non-problem at low boost on 2 exhaust ports ?

Just how much BOOST are you planning to whack into this thing ?

If you are going HIGH boost ? there are far better cooling mods you could contemplate... IMO.
Not to mention...
things Like cutting an extra Crank Keyway 180* from the stock keyway to HOLD the Blower Hub at the higher boosts ?

Just my opinion, no wars wanted.... maybe ask HIM why he recommends doing it ?

[Challenger340]

edit

[chargd72]

No thought of "war" was taken.  These are the opinions I asked for.  I believe Mike was pointing me to someone else's findings with racing small blocks.  I found the original concept on Moparchat from a guy named Harry Sanborn who is thought of as a God when it comes to small block cooling and oiling.  His argument starts similar to yours on how the coolant flows.  But he says the coolant will follow the path of least resistance claiming that most will go straight out the large exit hole (back of block) before properly cooling the last cylinders.  His words from Moparchat:

Let's review the water flow path through the block and cylinder heads:
Water is pumped into the 1" diameter hole in the front of the block. From here the straightest shot is to the back of the block and the 1" diameter hole there. That's where most of it goes. Sure, some of it goes down to the bottom of the block and goes up into the heads in the row of holes in the bottom of the deck of the block. But most goes to the large hole in the back. This is exactly what you don't want to occur.!!!!!! Block off that 1" hole in the back of the block, force the water down in the block and force it to come up into the heads through the holes in the bottom of the block deck. This maximizes the water flow around the exhaust valves(where most of your heat is). You want to keep your exhaust valve seats as cool as possible.
http://www.moparchat.com/forums/showthread.php?t=70569

I will be running anywhere from 10-12 pounds of boost and already have all necessary mods to keep me cool.  Good 3 row aluminum rad, '95 taurus fan, high volume water pump...  But like you mentioned I'm mostly concerned with block longevity. 

[Challenger340]

OK, I see the rationale, but I don't believe those guys have cut up a sbm ?

I've never cut an R3.... but on the stock blocks,
the coolant DOES already follow the path of least resistance at the front of the Block where it enters, where it is restricted internally along the top of the deck(smaller along the top) and "easiest" path(larger passage) directs it DOWNWARD on the deck ?
just sayín.....
if coolant follows the "path of least resistance", meaning "largest" water jacket areas to flow ?
* in the front
* DOWN at the front
* along the bottom to the rear
* UP and out the back
Not saying there ain't Flow everywhere else... there is, just the "largest" river is along the bottom in the 340 we cut up years back ? All I've ever seen on mopars is guys enlarge the gasket holes along the bottom ?

Not saying that their theory ain't sound either, because as I said, the heat load in the siamesed exhaust ports is an issue on ANY wedge ? and I've seen it done on other brands with sprint engines.
But I dunno about blocking the rear passage entirely with "just" a 1/16" hole in the plug ? somewhat larger would be my guess, because I still worry about cooling all the way to the back and the rear slug in the street environment ?

Just my thoughts.
hey... if they've tested it and seen results ? gotta respect them !

[chargd72]

I agree fully with the 1/16 hole sounds way too small.  Perhaps something closer to 1/8 to 3/16 would still benefit this concept.  Right now that opening is close to 1/4 npt which is fairly large.  Thanks for the discussion.  This is my first time using block filler so I don't quite know what to expect in terms of cooling.  I would like to hear more opinions while I finish oiling enhancements. 

[chargd72]

Bump.  For one last shot of gathering opinions.  Block goes back to the machine shop next week.

[cdr]

IF this mod was to be done, it should have been done before all the machine work was done.

[chargd72]

My post before yours.  "Block goes back to the machine shop next week."  It was there before for a flux and a bath.

[cdr]

the picture you posted is of a completed short block. but i get it,that is not a picture of your engine.

[chargd72]

the picture you posted is of a completed short block. but i get it,that is not a picture of your engine.

Correct