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"441" vs. "441X " head

24K views 16 replies 10 participants last post by  b-boy 
#1 ·
What are the differences (if any) between a "441" casting and a "441X" casting? Any performance gains of one over the other? I have just aquired a set of the "X" castings and am wondering if they are worth the time and effort to swap with the standard "441" set I am using now. Thanks
 
#3 ·
I wouldnt swear by this, but I believe that the x castings have slightly larger intake ports...normally about 10cc. It doesnt necessarily mean 2.02 valves though...I have a set of 487x castings that I have seriously ported but they came with 1.94's. I do know that the 461x has 10cc bigger intake ports than the standard 461. As far as swapping from 441's to 441x's, I wouldnt mess with it...you would be lucky to gain 10hp, unless you do some porting. 441's are about the best flowing 76cc factory heads you can get...if you was swapping from something like an 882 or 624 then you would see some noticeable gains.

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375hp 78 Chevy truck
77 Chevy Nova
95 Chevy Lumina 3.4L
and building a 78 Nova
 
#6 ·
You do know that you can have your heads cut for bigger valves right? Most of the double humps are 1.94/1.5, just take them to the machine shop and have them cut for 2.02/1.6 .
I have had many sets of heads cut for the bigger valves, and have never had a problem.
Just a thought guys. Ryan
 
#7 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by b-boy:
What are the differences (if any) between a "441" casting and a "441X" casting? Any performance gains of one over the other? I have just aquired a set of the "X" castings and am wondering if they are worth the time and effort to swap with the standard "441" set I am using now. Thanks<HR></BLOCKQUOTE>

Hi...
The 461 heads had 158-160cc runners...while the 461X had 175cc runners...
The 461 castings are not the most desirable chambers in the double-hump family of heads..
Theses had 60cc chambers instead of the normal 64cc chambers that came out later 1967..
The reason is that the 461 chmaber has a quench on the spark plug side..which limits using any dome piston...these heads are for flat-tops...and once these heads are decked more than once ..they are useless...since the spark plug hole is WAY TOO close to the face of the head...the next series of double-hump heads had the spark plug hole slightly higher in the chamber and they cast a angled relief above the spark plug hole ..thus making 64cc.. all the 461 and 461X castings had NO accesory holes...so use the short water pump set-up and bracketry..which BTW looks cooler.. Also..cutting the 1.94 intake valve seats bigger to accept 2.02 valves does NOTHING to help performance..infact it HURTS performance..I have flowed these heads and various mods and have volumes of documented data..... UNLESS you deshroud the chamber for the 2.02 there is nothing to gain...also below the valve seat..unless this area is apropriately enlarged and bowl blended in...the 2.02 valve will do nothing more... Otherwise you are throwing money away...on the other hand..It sounds cooler to say you have 2.02 valves

CHEERS
Chris
 
#8 ·
My stock 2.02"/1.60" valve -461 heads have 66 cc chambers w/ factory reliefs around the intake valve.

I suspect they came off either a '65/350hp/327, a '64 or'65/365hp/327 or a '64/'65 375hp/327 fuelie engine. They all came w/ domed 11 to 1 compression ratio pistons. The '67/325hp/327 engine was in there too somewhere.
 
#9 ·
Originally posted by pdq67:
My stock 2.02"/1.60" valve -461 heads have 66 cc chambers w/ factory reliefs around the intake valve.

OK...so someone de-shrouded the chamber for the 2.02 valve to breath better...This is probably how these 60cc chamber got up to 66cc's......Are you sure the factory did this??? and not done by previous owner of the heads???

They all came w/ domed 11 to 1 compression ratio pistons. The '67/325hp/327 engine was in there too somewhere.
Yeah..you can use a "small" dome to get the 11:1 thing happening...but the flame travel with the low position spark -plug is not that cool... also after the heads are decked a few times this could be more troublesome...
CHEERS
Chris
 
#10 ·
All 461X heads were 1.94 in and 1.50 ex the latest set that I have seen is OCT 1961. I don't think anyone has really explained why they exist you could find them on anything that was a HP. motor. I used to get $500 for bare castings when $500 was a lot of money. All of the Ecno dragsters used them and those guys ran 13to1 compression or more. I guarantee you if there was anything better they would have run them.
 
#12 ·
441X came on trucks, 1969-72, and some 400 small blocks. I have had 441x's and the valves were 1.94-1.50 factory and compaired to a 441, they appear the same, I have had both heads, they are good for mild use. Both heads are the same casting, same cc chamber, no difference between the two, except steam holes for 400's.
I have had both, unbolted from factory cores, and have never seen or noticed any power difference. The 461X is the only head # that ends with an X, that is a performance Chevy head. Check for cracks around the exhaust seats.
 
#13 ·
B-boy,

Sorry to have mouthed off about the -461 heads since you asked about -441X ones.

cerrem, Mortec lists -461's as coming off '64/'66 327 engines. And only the H/P engines had the 2.02"/1.60" valves. And to put the big valves in the standard head casting, the Factory reamed out the combustion chamber to unshroud the intake, thus the increase in cc from a nominal of what 60/64cc??

Only the H/P 327 engines had high dome pistons, all others were flat top like the 300hp/327 and lower! As for the 60 cc castings they were probably used w/ 1.94/1.50" valves on the lower engines too. Mortec lists the -461X as being used on 283 and 327 engines but NO 283 had big valves, but only the little 1.72"/1.50" valves. Apparently the Factory thought the 3.875" dia. 283 cylinder would choke the big valve heads tooo much so didn't install them on the little engine. IMHO!!!! pdq67
 
#15 ·
Oger,
Where's your source of information so I can learn more??

I was under the impression that the 315hp/283 was F/I and the 290hp/283 was 2/4's, but that both had the small heads and little Duntov cam and rams-horns.

Heck, maybe I'm thinking of the 270hp/283 w/ the dual carb's?? pdq67
 
#16 ·
Well, Since the topics slid over to the 461's and the "X's", the only difference is the 461X has about 5-10cc more cross-sectional area in the push-rod constraint area. These heads have volume tolerances that varies. The volume of one intake runner, as well as the combustion chambers, may be different from one head to the next. Nothing excessive, but they do vary.

Now to the 441's. I have ported and set up the 441X head for decent street use. I don't have my resources right under my fingers right now, this is just off the top of my head, but I think the 441X did come on some of the smog burdened Corvettes of the 70's. You will find though that the 441 is very competitive with the 882 head which is commonly touted as the best of the smog heads. What makes these heads less desirable is not the large combustion cambers but the design of the chambers. They are squared off and difficult to work with. You can port and polish all you want but what happens after the intake valve closes is very important as well. You will probably find that the 441X's have the 1.94 intake, 1.50 Exhaust. I cannot vouch for the 441, but I think they will be smaller. I would be willing to bet though that valve size is the only differance. Anyhow, to answer your question. If you was only intending just to swap heads, don't waste your time.
 
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