440 Rebuild - Should I drill holes in my Heads????

[BSB67]

No - shooting for @450HP, going with stock HP intake and '67 HP exhaust manifolds, the heads have the bigger 2.14x1.81 valves and HD springs - to go with Comp Xtreme Energy 268/280 duration, 110 deg sep, .477/.480 lift - matched with B&M 2,400 stall - and will be paired with 323 0r 355 sure grip (would like some advice on that choice too - would be willing to sacrifice a little out of the hole for some flexibility for doing some up to 2-3 hr road trips) Will be running @ 235-60R 14s.

Doable, but the intake will be what hurts you the most in reaching that power level, assuming you are using a good exhaust system with the exhaust manifolds.

I had a similar set up years ago in my 67 Charger.

 

[66Satellite47]

OK - so here are pics of what I'm talking about #1 is my '73 block (I'm pointing to the same spot in all 4 pics) #2 is my son's '76 block, #3 is a gasket from his '76 452 heads (we just dropped them off at the machine shop), #4 are my just purchased 452 castings, which do NOT have these passages. Since my block does, I COULD take advantage of extra cooling by drilling the holes in the heads (same castings would indicate that there is room for the cooling loop in those heads, right???View attachment 994008 View attachment 994010 View attachment 994013 View attachment 994015

See post#20. Your new heads are not he same casting as the ones that go with your block.

 

[Todd Schuster]

I'm not sure you would be drilling into a water jacket on that head.

I'm betting you son's heads are the taypered plug and yours are the flat plug with the metal ring.

https://www.forbbodiesonly.com/moparforum/threads/spark-plug-help.179931/

Wow! Kind of crazy that Mother Mopar wouldn't have changed the casting #!!!

 

[Todd Schuster]

See post#20. Your new heads are not he same casting as the ones that go with your block.

Very interesting - same casting #, but a different casting...thanks for the heads up- not drilling my heads!!!!!!!

 

[66Satellite47]

Very interesting - same casting #, but a different casting...thanks for the heads up- not drilling my heads!!!!!!!

Is the whole casting # the same? 4006452?

 

[Todd Schuster]

Is the whole casting # the same? 4006452?

YES!

 

[66Satellite47]

Can't imagine why Mopar did that. I never ran the 452's you now have, looked over a few though. I knew at least one very successful bracket racer that used the ones you have, heavily ported by him.
Edit: I'm sure the cooling on yours will be just fine.

 

[Brandy]

Those MH water pumps also have a sewer drain compared to the car ones. Flows much more water through there.

 

[origcharger]

Some Motor home/Medium duty truck big block engines used these heads

 

[Tim L Stockwell]

Years ago, I drilled holes in my head. Big mistake. Every time I drink a glass of water, it leaks all over the place.

Good one!

 

[kbfallon]

See pics below (or above?)

I think, I would take a few minutes and call one of the companies who make these products or use them.....Indy cylinder heads or Haines......or? It will give you piece of mind and you won't be wondering after the fact.

 

[MoparDanMan]

I bought a '73 440 - has been bored .30 over - I have a fresh Steel Crank to go in the block, std bearings. I was unaware that this block was a Motorhome block until I realized the extra water passages under each cylinder. I purchased a set of reconditioned 452 casting heads from Arrow Heads thru Indy Cylinder Heads (chose those over 906 for hardened seats) - I was told by a couple friends to take advantage of the water passages and drill holes in my new heads for the extra cooling (will help on deterring detonation pings - esp w today's poor gas!).
Has anyone done this? I don't want to mess up the $ I just paid for brand new heads!!!

Simple answer NO!