I'm going to the boneyard and machine shops this week-end. Going to look for a good pair of heads for a 350 which casting number should I look for to get the best heads? How do double hump heads look like?

The last three numbers in the seven digit casting number are significant on SBC heads. Some good casting numbers are:

191,192,461,461x,462 All of these heads are early and have no accessory mounting holes for the '69 and up "long w/p" alternator mount.

186, 187 and 414 These are later model and have the accessory holes. The 414's were the 70 LT1, 370HP head!

The "Camel" or "double" hump refers to the casting mark on the front and back of the head. It's very distinctive and looks like two humps on a camel's back! (Or your favorite girlfriend lying on her back!)

For more casting numbers go here: http://www.mortec.com/castnum.htm


You'll have a hard time finding any of these heads in the bone yards! Guys like me used to walk around for hours on end in the 70's and 80's pulling them off of junkers! They also have some problems to look for. Big springs can crack the spring pockets. Heads with 2.02"/1.60" valves can crack between the intake and exhaust valves. Some don't have a lot of meat to grind for porting.

I think I have a good set of 462's with 64cc chambers, 2.02"/1.60" valves, big springs, screw in studs, and guide plates if you're interested. Lemme know.


[This message has been edited by PDQUICK (edited 12-05-2001).]

[This message has been edited by PDQUICK (edited 12-05-2001).]

I saw some heads at a machine shop and the casting numbers on those was 462624 are these heads any good? By the way does it matter on the cc size? Or is it the valve size that gives it it's power?

[This message has been edited by 4U 2 NV (edited 12-05-2001).]

Are you sure they aren't 462's? I dunno what a 624 might be, and the casting numbers are usually seven digits.

The "cc" number refers to the volume or size of the combustion chamber measured in cubic centimeters (cc's). This makes a huge difference in your engines static compression ratio. Chevrolet made good heads in two basic chamber sizes, with slight variations, for small blocks engines. Early high compression engines had small 64cc chambers while the later, low compression, "smog" engines had 76cc chambers. This is how they dropped the compression numbers for all engines by a couple of points in 1972-3.

To a point, the higher your compression ratio, or the more you squeezee the mixture, the more energy or power you can get out of the engine.

Larger valves and ports allow the engine to breathe more efficiently and therefore make more power.

[This message has been edited by PDQUICK (edited 12-05-2001).]

I didn't see the 041's 041x's mentioned. This is a well flowing head/ It is a hidden camel hump. Flows about 165 untouched!

Yeah, lineus is right! The 041 and 041x were the 69 and 70 302, Z-28 heads! They have 64 cc chambers and late model accessory mounting holes and flow great!!

Thx

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Paul D.

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68RS, 331, 10.5:1, 4spd, 3.90 9", lowered, 245-45-16's all 'round

Before you go plop down cold, hard cash on some used 350 heads I would seriously recommend checking out prices out some aftermarket castings. There are inexpensive iron and aluminum aftermarket castings that outflow the best GM heads. The cost is not as big of a difference as you might think these days and in some cases it is actually much cheaper to buy new aftermarket heads than rebuilding something used.

Iron heads $500 - $800 assembled to look at: 1. a new set of Iron GM Vortech's 2. Dart Iron Eagles. 3. World products Sportsman or SR heads

Aluminum heads $700 - $1000 assembled to look at: 1. Trick Flow 23* heads 2. Canfield 3. Edelbrock Performer RPM 4. Aluminum GM vortech's

Unless you get a real steal on a set of lightly used camel hump heads or equivalent, you may wind up putting a lot of money into rebuilding old heads. The "good" late 60's castings have been well known by hot rodders for years and most of these heads are all used up (meaning they've been used, abused, and reused) - especially back in the 70 and 80's when good aftermarket heads were not readily available.

Just my opinion, good luck with the search.

ps. I'm running Trick Flow 23* heads - picked them up from Summit for $850 assembled.

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68 Camaro, 383 small block with TH350 trans. 11.98's at 111mph and never trailered.

By the time you get boneyard heads cleaned up and ready to run, you'll have spent $300.00 at the machine shop. This makes free heads not worth the money IMO.

My 993's have more in them than a set of iron aftermarket heads would have cost me.

I try to learn from mistakes, and know where to go next time.

Don't forget about the -291's.

And yes, by the time you spend money on the old heads making them "modern", you can buy a set of W/P's or aluminum, Canfields bare and have something better to start with. The Vortec's are even a better proposition after you factor in a new intake.

Thats why I went oval Merlins on my big engine. Imho. pdq67

I've got a set of 041's. they came of a 1970 2 barrel engine/never touched/machine shop cost for 202-160/screw-n studs/guide plates/3 angle valve job/no port work/as we all say,expensive/$500.00 According to record''s these heads flow from 161-165/65 I think, on the exhaust side: This is 2 give a little info on rebuilding or buying out of the box!


lineus:


[This message has been edited by lineus (edited 12-09-2001).]

There are 2 different 624 heads...on is the 1.84/1.50 valved 305 version and the other is the 1.94/1.50 valves, 76cc 350 version. I would have to dig for the complete casting numbers but I do know this...the 305 624 heads are pretty good as far as 305 heads go...the 350 624's are pure junk. Very thin castings, very poor ports, and they crack if you look at them wrong. Mostly used from '78 to about '83 or so. In the words of Montey Python...run away!

<BLOCKQUOTE>quote:</font><HR>Originally posted by 4U 2 NV:
I'm going to the boneyard and machine shops this week-end. Going to look for a good pair of heads for a 350 which casting number should I look for to get the best heads? How do double hump heads look like?<HR></BLOCKQUOTE>

The only time it pays to go this path is if you do your own work on the heads...
If you port-match, open the bowls and polish yourself..then it will be worth it...
You can even install your own bronze wall guides..
The only thing you need machine shop for would be to cut the seat and possibly deck the head, but thats ONLY if it needs it..decking should not be automatic when going to machine shop...use a straight edge and rolling paper as a feeler gauge to check the deck..
Regards
Chris