Hi all. Found some goodies today. I didnt know if this was the more appropriate spot to ask about some double humps or the engine one. Figured this one cause they are historical! So buried in my dads shop of Manley Old Everything A guy could think of, I found some double humps. Awesome shape. Looks like they were in a dip tank and then heavily oiled like everything else there. the numbers are 3917291. I looked em up, and they are for a 302, 327, 350 it says, 2.02/1.60 64cc with no acc holes. I always hear about these and I couldnt believe what I was seeing when I saw the humps. they are matching numbers except for there is a K25 on one and a K24 on the other in between guides on top side of head. there is also a big Z in between another set of guides.

1. How rare are they?
2. What would be the best block to put them on?
3. How much are they worth? (as much as someone is willing pay for them)
4. What do the K24 and K25 and Z mean?
5. Could they be for a old vet?

I also have some other complete heads I built with k-liners, manley swirl valves. 1.94/1.5 75cc. says on a head look up that the intakes are 1.72 but i know i put in 1.94. the numbers are 3998993. Are they a decent head? they started out on my stroker. maybe have 3000 miles on them. any info is appreciated but my main focus is the double humps.

 

Sell them to someone that wants them for a restoration (or boat anchor) and use a newer better head (like the vortec truck head, if on a budget).

 

I sorta agree with TTop350.

The double hump/camel hump/camel back heads WAS great, 40, 50 years ago. Much better head designs out there now. In fact the 96-02 vortec truck heads are the "double humps" of now. They do everything much better than those 50 year old heads.

Sell the hell out of them. I have seen double humps go for $800. More common is $300-500 though.

Take that money and put towards a $1200 set of aftermarket heads and enjoy the 75 HP gain over what the double humps would have made.

With out any port work those 291 heads will flow around 193/146 cfm
The vortec heads flows 225/152
Most of the good aftermarket heads.. AFR, Brodix, dart, edelbrock, Jegs, Pro filer, etc flows in the 250/170 cfm and up range.

Head flow is just one part of a good head too, so look at other things like the newer heads have the fast burn chambers, etc etc

 

What they both said.

Some of the best heads of their day; but that day is LONG gone. Especially for the various ones without the bolt holes, which also are without the "squish" feature under the spark plug, which renders them incompatible with modern gasoline as well as technically inferior in a major way.

But, the "nostalgia" crowd eats em up; "recycle" em to someone doing a "number matching" type deal.

K24 & K25 sound like the date codes, except that there's usually another number behind them. They would mean that they were cast on the 24th and 25th day of month K (12, Dec). The 4th char should be the last digit of the year they were cast.

1. Depends on how you define "rare". In stock unmolested shape, getting harder to find.
2. Someone else's SBC, who isn't looking for a competitive-running vehicle, but just wants th eold stuff.
3. Exactly: what someone who wants them will pay, and that you are willing to accept
4. Covered that
5. Sure, lots of old vets might like them, esp from the Vietnam era

 

Those heads were used from '62-'69. I'd try to sell them to someone restoring a 1st gen Z28 or similar who needs date coded, numbers matching heads. Probably your best bet is to haul them to a swap meet.

 

A friend is running a set of 1.94 camel hump heads on a 327 he pulled off a 283. He replaced his set of 305 heads with them and also used a performer RPM intake instead of the single plane he use to have and it runs awesome. But my vortec 350 is almost as fast and I am running a way smaller cam, smaller intake and a vacuum sec carb. His cam is about 10* larger and has a little more lift than mine. Other than a set of vortecs or aluminum L98 heads I would use the camel hump heads over a regular stock set, they work great for a stock set of heads. I would not pay more than around $200-300 for a good set. If you start to get in to new head prices you might as well reap the rewords of new castings that flow better.

 

they might be worth a few more bucks if they have factory installed screw in studs and a date code that matches a 67 or 68 Z/28 that someone is restoring. i think they used those heads on the higher hp 327's in Corvettes, too, and those guys love to spend way too much money for parts for their cars..

 

Thanks for the info guys. This site is full of very knowledgeable people. I read a bunch of other forms about the humps and was a little shocked that they arnt as good as I thought they were. I totally understand why. I think, unless I can find someone to buy them for a decent price, I will keep them. I already re-coated them in a moisture/water rust protector. I bet in 50 more years they will be a hot item. And not that they arnt now, its just a certain small group that would want them. I have a set of Dart pro 1s on my stroker and love them, and I agree that the humps couldnt compete with newer stuff. Or a guy would have tons of money and time into them.

Are those 993's any good? I cant find really much on the web about them.

Thanks again for all the help guys. Im glad I joined this club. Wonder why I didnt sooner......

 

If they have factory screw in studs than they were on a motor that had a solid cam in it. If there pressed in it was a hydraulic cam. If you have them than use them they are good for a factory head. I would try to trade them for a set of vortecs if your not going to use them.

 

No.

Just another one on a long dreary list of smogger crap from the 70s, along with 882, 624, etc.

 

From a performance view, No. For a general stock replacement head on a daily driver, sure. The 993 casting is a heavy casting smog head. Highly unlikely to crack and should last for years with no problems. GM used these castings on many of their stock replacement crate engines.

If you want any sort of performance production head, your best choice is a vortec head. If you try to make a production head better for performance with bigger valves, port work, screw in studs etc, you'll get more bang for your buck buying a set of good aftermarket heads. All the required work will be done, better castings etc and will be far cheaper after you calculate all the labor required to make production heads better. Even a set of aluminum aftermarket heads are not an exotic option any more. They are more affordable now than they were 20-30+ years ago.

 

993's and their 70s (and 80's.... although the LB9/L98 stuff was decent) ilk are the reason people have so much nostalgia for the double humpers.

We surpassed those long ago, but there was a time when they were the hot ticket, because things like 993's were all anyone had.