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

Todd Schuster

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Almont, Michigan, USA
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!!!
 
You better make sure you can get a head gasket that will work with the holes that you are thinking about.. I personally wouldn’t do it..I would verify with a pro mopar shop where and what you should ... it’s better to error on the side of caution unless you have some radical build. I used a 73 block and with aluminum heads and didn’t do anything like that, no problems.
 
Years ago, I drilled holes in my head. Big mistake. Every time I drink a glass of water, it leaks all over the place.
 
Years ago, I drilled holes in my head. Big mistake. Every time I drink a glass of water, it leaks all over the place.

Ta Dum
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That sounds like some urban myth or internet BS.... I DEFINITELY would not be drilling any holes in new heads.
 
How much horse? 800+?
 
I doubt the cooling would be improved. It's not the block that improved motor home cooling, it's the different head casting with different passages in the heads. Do the pocket porting on the 452's to improve the flow, HP, torque whilr you have the chance.
 
I doubt the cooling would be improved. It's not the block that improved motor home cooling, it's the different head casting with different passages in the heads. Do the pocket porting on the 452's to improve the flow, HP, torque whilr you have the chance.
That was my question - I was told I could add the passages by drilling the holes in the 452 heads!!!! My son got a known motorhome 440 with his '66 Charger that had the 452 heads with the passages, so obviously those are in the castings, right? (I think I may have just answered my own question?!?!) Just looking for confirmation.
Thanks for the tips on the pocket porting, btw - will be doing this.
 
How much horse? 800+?
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.
 
Well I guess I'm confused, post #1 says you have a motorhome block and a set of recon 452 heads. Not sure where you drill holes in the 452 heads to improve cooling. The motorhome heads I have seen pictures of, have a different internal water passage around the spark plug area and didn't think they were 452's. Good luck.
 
Well I guess I'm confused, post #1 says you have a motorhome block and a set of recon 452 heads. Not sure where you drill holes in the 452 heads to improve cooling. The motorhome heads I have seen pictures of, have a different internal water passage around the spark plug area and didn't think they were 452's. Good luck.
Yes - the 452s came on motorhome 440s (my son has a pair sitting in my garage!) - and they have the extra water passages. The 452s that I bought do NOT have them. My block has those passages , so it must have been a motorhome engine. Since they are the same casting # - I assume I can just drill the holes in my new heads (I have templates in my garage via my son's heads!) - that should help increase cooling, not a bad thing, right? Notice I said ASSUME in the prior sentence - I am just looking for confirmation that I'm not going to destroy my heads with a drill bit!!!!!
 
If you look at the head gaskets you will notice that the area on the gasket that lines up with the "8" shaped holes on the block are just narrow slots. Drilling the heads aint gonna help.
 
If you look at the head gaskets you will notice that the area on the gasket that lines up with the "8" shaped holes on the block are just narrow slots. Drilling the heads aint gonna help.
I'm not talking about those passages - there are 2 small holes that are at the BOTTOM of each cylinder. My son's '76 452 casting heads have holes in them that angle up and alongside the spark plugs that align with those holes at the bottom of the cylinder in his block...my block ALSO has those holes below the cylinders - but my passenger car,"new" 452 casting heads do NOT have these holes that go up alongside the spark plugs... Apparently, nobody does this, so I'm thinking I'm just gonna leave my heads alone. (I was under the impression that this was a common mod - and that I could take advantage of some extra cooling, but I looked closer at my son's heads and these holes are DEEP and on a 2 axis angle...not gonna mess up my heads...not worth it!
 
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???
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Could be wrong, aren't the heads that go with that block a very different casting, with obvious difference around the plugs, and the spark plugs are not the standard BB spark plugs, small thread, small hex? Pretty sure I've seen pics of the very different castings, didn't think the full casting #'s were the same. Folks that know more than me can contribute.
 
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