Hot Rods Chevy heads 461-462

OK, I'm confused. Concerning the camel hump heads on 327 engines, which ones had 2.02 valves and which had the 1.94's. I'm getting conflicting opinion on which are which. Any experts out there?

 

Check this page out:http://outintheshop.com/faq/casting/heads.html. There were many castings that ended in 462, but had different overall numbers. For example, in the mid sixtys, there were heads with the same casting numbers ( ending in 462) but had either 1.94 intakes or 2.02 depending on application. Also I know from experience that many 1.94 heads were opened to 2.02.

 

Both of them and a 1 cc difference.....

 

Joel is dead on, many machine shops would hog out 194's to 202's

 

On a street engine, would there be any real world difference between 1.94s and 2.02s?


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Yes …. above 5,000 RPM, the 2.02 breathes better providing you have the carb, cam, gears, & headers to take advantage of them.

 

"Just" installing a larger valve...is NOT...a guarantee of a positive difference, or any notable difference at all.
90% of greater performance when installing larger valves...is what's happened between the valve seat and the bowl (to the port roof) after the seat was enlarged.

IF...proper preparation/reshaping was completed from the valve seat to the roof of the port was done, then from about mid lift (.about .300" lift)., yes, power might be seen. To whatever full lift is (in the .550" range), also yes, there will be gains...as long as the entire port is "well shaped".

Again, much more than...just a larger valve is required to gain performance from the dollar/time spent to install larger valves.
If you don't want to spend the money on well done port reshaping, then don't waste your money on larger valves.

I've reshaped ports with valves .06" smaller than the "excepted" diameter and got equal flow numbers from the smaller valve vs. the larger valve. Again, it just depends on the preparation above the seats.

P.s. - If you need to run iron heads, find a set of 461x heads (has the "x" cast in next to the casting number). They have better flowing ports, which goes along with larger valves.

Mike

 

I think a lot of them were done to sell for more money at swap meets to a person who didn't know what he was looking for.

 

I've only had a few sets of 461 heads, all had 1.94/1.5 valves. I'd "heard", but never seen, they would come with 2.02/1.6's. Never had 462's. Mike WV mentioned 461x heads, I never saw a pair off an engine, the one set I saw on a car, the owner told be they had a larger intake runners and "the bigger valves", than 461's.

Incredibly helpful, I know

 

As I recall from back in the day, the 2.02 intake helped all out drag cars, but on the street 1.94 had excellent, maybe better performance.
Of course a lot depended on camshaft and other factors.
OP, what 327 spec are you building to?
Cam, compression etc.

Phil

 

461X heads have a 10cc larger intake port. 170cc intake port for the 461x vs 160cc for the 461.
The X on the 461X heads CAN NOT be seen from the top side of the head. The X is cast on the bottom side under the water passage near the end of the head. The X in a 461X head is NOT cast on the top side of the head with the 461.

 

I am building a 327 for the 55 and I have a set of factory 461s to go on it. I snapped a few pics. Factory 2.02s and I know the car they came on. Date code July 31, 1965. Performance? I will take the big valves on iron heads all day long. Will you know the difference? Maybe, maybe not. Chevrolet put em on there for a reason and that works for me. I will go with flat tops and a crane copy of the 327/350 HP cam shaft. I have built the same set up before and it felt like you were being pulled by a rope.

 

This video shows the difference between 461 and 461X on some take off heads that have been on the self for many years.

 

The 57 powerpack heads on my 69 -327 have a X cast on the outside of the head[ . I have a set of 461 double hump that I installed the larger valves. I notice the stainless valves did not surface rust. they don't have any X on them.

 

And, they were only made in '61,'62, and '63. The "X" will not be right next to the 461.

 

Lots of different "things" guys claim about the 461/461X heads. But first of all, let me address Old wolf, and his Power Pack heads with the "X" on the exhaust side outside; there's probably a "58" somewhere on the outside also; those are "probably" 1958 Power Pack heads, and are also probably drilled/tapped on only one end of the heads for the Air Ride suspension components, that were bolted to the head, and that was optional that year (only year for the Chevrolet Air Ride). OK. Now, I've been "told"/"read" the 461X heads had 62 CC chambers, as opposed to 64 CC chambers of the "non-X heads, and that the extra volume of the intake ports came from the very slightly raised roof of the intake ports. And, I've also been "told", and have "heard", that the "X" of the 461X heads, are cast underneath, and can't be seen without removing the intake manifold, and using mirrors, or a bore-scope to read the X. Or unless the heads are off the engine, and turned upside down to rear the "X". At least that's the way it is on MY 461X heads that happen to have Manley 2.05 intake valves and 1.6 exhaust valves). There used to be a member named William's (a guy local to me actually), who had a long, ongoing thread about the camel hump/double hump/fuelie/whatever you want to call them, heads. Maybe someone (moderator or Ryan) can find that for us, because it was very accurate and educational. And like Forrest Gump said, "and that's all I've got to say about that". I am Butch/56sedandelivery.

 

I'd think if the volume of the intake runner was affected my the CC, wouldn't the larger CC wind up wit more volume?

I was also "told"...lol..that the runners from the intake to the chambers were larger, your 170cc you mentioned is what I recall...I thought I recall the 461's (non-X) to be at 160 or 165cc.

Would be nice for those holding them to look them over and confirm/deny.

 

Everything I have ever read states 160cc for non "X" format 461.

 

Ya, that was mis-worded. If the CC is larger, the valves would be higher "into the chamber", the actual volume of the chamber should be smaller, unless the runner was larger....which as I understood the x head had a larger runner size.

I'd guess a look at stock intake gaskets for each head application could confirm/deny this?

 

Save your money pocket port them instead.

 

@cheepsk8, I don't want to break your bubble, but those are not factory 2.02's. If the were, the chamber wall around the intake valve would be machined to unshroud the valve. Your's look to be rough cast, just like factory 1.94's. Mike VV is correct, the "X" will be on the TOP side of the head, after the 461 (3782461X) not sure what the "X" on the bottom side means but I have a pair of '65 casting's with the X on the bottom on my engine right now but I'm not about to pull a head to take a video and post it. The 461X casting's were early casting's, like has been stated, 61, 62, early 63, and if that's the case, would be 1.94's. 2.02's didn't come out until the '64 model year. (later 63 casting date)

 

The 461x 's I owned did NOT have the X on the top side, only the regular casting #3782461. I would like to see a pic of a rocker arm valley with the X in the casting# and a corresponding date code...

 

@Budget36 I think you are looking at this wrong, it is not the port opening at the intake surface but rather the approach to and the radius itself that was increased where the port turns toward the valve bowl. The chamber CC’s could either have been reduced by a slight reconfiguration of the chamber as cast or milling the head surface a bit more.
I’d like to see a photo of a head cast with 3782461X too, I never heard of that before. I do have some ‘441 castings with the X on the bottom. ‘441’s are from the ‘69 255 horse 350 and were considered a decent smog chamber head BITD, but does the X mean anything? Who knows, maybe it was used on the ‘441 head as a casting identifier.

 

I have a set of 441x for a someday blower motor. The X for those heads denotes a 80cc combustion chamber rather than 76cc of the 441 head. I can get by with still using forged flat tops and keep compression ratio down.

 

Well it's not the first time it has been busted. Interesting that these heads were redone before 1972. Bought them off a buddy short on cash for 50 bucks in 1978, and he had the car for at least six years before that, until he wrapped it around a light pole. I guess it was popular to re-valve them back then. Still, I am going to use them as they checked out crack free.

 

WRONG!!!
You will NOT find a head or a real picture of a 461X head with the X on the top side of the head following the 461. GM did not make them. The X on 461X heads are on the bottom of the head.

 

If that's the case, and the X heads were only made from 61 to 63, how do you explain the 65 casting's that have the X on the bottom that are on my engine? I know they exist. I've seen them, I've held them, and I've heard them running on a 62 fuelie Vette! Could it be that the ACTUAL 461X heads are being confused with other X's? Could it be that real 461X heads are so rare that all the Corvette guy's scarfed them all up for their super rare fuelie pipe dreams? I don't know, just saying what I've seen, held , and heard.

 

My power packs are extensively modified 57 heads casting date G87 no drilling or tapping on the ends of the heads. They came from the very first 55 I ever bought. Got it from a older Pot Smoking guy named Ed. He just got home from as he put it a free vacation in southeast Asia courtesy of the Army and had bought a 396 chevelle. He told me the 55 ran like a Raped Ape! First time I ever heard that saying. It had a 56 block bored to a stock 283 bore flat top pistons without any valve reliefs. It had a carter afb on a 327 intake and a 30 -30 cam. I not knowing better set the valve lash at .012 and .018. and collided the valves with the pistons at high RPM. blew that piston completely off the rod. In the past I also had another 57 engine with the X on the heads. Still have that 57 block. I don't think the X on powerpacks means anything.

 

You are confused. 461X heads with the X following the 461 on the top side of the head do not exist. If they exist the way you say and you are so sure that you've seen and held them, it will be easy, especially with the internet, for you to be able to post a picture example of what you say you held. I won't argue dates, but I'm sure you won't find a picture of a 461X head with the X following the 461 on the top side of the head. Prove me wrong and I'll gladly and humbly eat my words. Thanks.

 

I believe your are correct wolf... I would be willing to wager to see an image of a date cast head of '65 with an "X" on the bottom side. With the intake off, they can be spotten with a dental mirror...