First timer seeking wisdom

[spinning wheels]

Double hump heads were a good design back in the late 60's, early 70's. The motors with these heads were installed in chevy's lighter cars. Most (not all) of these cars also had high compression pistons, solid cams and heavy duty valve springs, 1.94" or 2.02" intake valves.
Then again, back then you could buy 100 octane gasoline at your local gas station. Today there are better designed heads available that can run on the lower octane fuel. it all depends on where you want to make your power. Most hi-po heads, will make more hp in the higher rpm range. Not sure if that is were you want to make your useable hp and torque, when the motor is going to be used in a daily driver truck.

One thing to consider, is what you are going to be using your truck for.
For example. A friend of mine had a very clean 68 LWB, he installed a nice running SBC with a 700r4, with disk brakes up front. As nice as this truck was, he wished he had gotten a 3/4 ton truck, because he was towing race cars and project cars, more often than he had planned for. He liked the bigger brakes on the 3/4 ton trucks vs the 1/2 ton. He ended up selling the truck for little over 6K. He was able to get that kind of money back in the late 90's. Not sure if he would have gotten that in today's economy.

It also comes down to, how much money you are willing to spend on the truck. Or, how much mechanical abilities you have.
I swapped my 3/4 ton truck, for an '88 Ford Ranger I had, with cracked heads. Then again, the GMC had been sitting in a back yard for 6 years and had plants growing thru the suspension. I needed a tow truck to drag it out. I have since done a lot of work on the truck, and the truck still looks like a beater.

Ok, I'm stepping off the soap box..... Hope this info helps in your decision.

[sameyrasmea72]

I was reading one of my parts #’s books the other day and it said there were a lot of double hump heads back in the days but very few of them were the high performance variety. Most people see the double hump on the head and think they scored big time. Best to check the #’s

[67_C-30]

Originally Posted by sameyrasmea72

I was reading one of my parts #’s books the other day and it said there were a lot of double hump heads back in the days but very few of them were the high performance variety. Most people see the double hump on the head and think they scored big time. Best to check the #’s

That's true to point, but all double hump heads had small combustion chambers and high flow intake and exhaust runners. The double humps only came on 4bbl engines. None ever came on a base low performance 2bbl engine. The difference in the reg double humps and high perf ones was 2.02"/1.60" valves and screw in studs and guide plates. The castings were not different. Any double hump is a upgrade in performance over a low perf or 70's - 80's smog head in terms of performance.

[67_C-30]

Originally Posted by spinning wheels

Double hump heads were a good design back in the late 60's, early 70's. The motors with these heads were installed in chevy's lighter cars.

Double humps came on as many Impala engines as they did anything else. The vast majority of double humps came on flat top 275HP 327's and in later years 300HP 350's. The dome piston, 2.02"/1.60" versions were way less common. This is a common misconception with double hump heads.

[spinning wheels]

Originally Posted by 67_C-30

Double humps came on as many Impala engines as they did anything else. The vast majority of double humps came on flat top 275HP 327's and in later years 300HP 350's. The dome piston, 2.02"/1.60" versions were way less common. This is a common misconception with double hump heads.

You may be right, that the "double hump", or "camel heads", came on the Impalas. I know that in the early eighties, they were highly sought after. This was before aftermarket heads came upon the scene at affordable prices. The early heads were not drilled for accessories, like the later 350 heads.
So most people would pass them up, in favor of the newer camel heads.

Regardless, on a truck, I would rather install a good set of GM 350 cu.in. Vortec heads. The Vortec heads produce very good low end torque, which would work much better on a truck.

[Griffin]

I'm new to this board too but i'm not new to rust repair. I'm in Fayetteville with you and would be happy to help you find a truck or give you some pointers on rust repair. I would have never learned how to weld, spray paint, or rebuild engines if someone hadn't shown me. The top of my 67 GMc just got crushed by a tree and i'm about to start the body work to fix it. Check the Fayetteville and Joplin craigslist under "auto parts" and "cars and trucks." There were several trucks listed in there listed over the last few days. Let me know if i can help.

[sameyrasmea72]

Originally Posted by Griffin

I'm new to this board too but i'm not new to rust repair. I'm in Fayetteville with you and would be happy to help you find a truck or give you some pointers on rust repair. I would have never learned how to weld, spray paint, or rebuild engines if someone hadn't shown me. The top of my 67 GMc just got crushed by a tree and i'm about to start the body work to fix it. Check the Fayetteville and Joplin craigslist under "auto parts" and "cars and trucks." There were several trucks listed in there listed over the last few days. Let me know if i can help.

Sweet offer. I wish someone in my town would give me some tips on rust. Believe it or not we do get SOME rust in west TX.

[67_C-30]

Originally Posted by spinning wheels

You may be right, that the "double hump", or "camel heads", came on the Impalas. I know that in the early eighties, they were highly sought after. This was before aftermarket heads came upon the scene at affordable prices. The early heads were not drilled for accessories, like the later 350 heads.
So most people would pass them up, in favor of the newer camel heads.

Regardless, on a truck, I would rather install a good set of GM 350 cu.in. Vortec heads. The Vortec heads produce very good low end torque, which would work much better on a truck.

I agree that Vortecs and all of the aftermarket heads are better. I'm not arguing that. I'm building a new engine for my red '69 right, and I'm using Vortec heads on a '90 roller 1 piece seal block with a roller cam because it will give me optimum performance with maximum fuel effeciency out of an Gen I engine. An LSX engine would be even better, but I'm building what I have.

I'm only stating the double hump is still a very good head. They are not the huge port, high RPM performance head a lot of people think they are. They make tremendous low end torque, and still flow better than any production Gen I head besides the Vortec and LT1/LT1. The early 291's, 292's, 461's and 462's had 160cc runners and the later 186's, 414's, and 492's had 165cc runners as opposed to 170cc runners on the Vortec. I have ran them on everything and they work great. I'm running a set on the engine '69 ramp truck and torque is no issue. They are a better truck head that any truck head of that era.


JesseSimon, sorry we have strayed off subject! To answer your question double humps are pretty good heads, but I wouldn't call them special. They are definitely much better than anything that would have came on the truck. I wouldn't pay a lot of extra money just for them as 70Custom10nut said. As spinning wheels said, there are better modern heads, so don't buy a truck just for a set of not-that-special heads.

[JesseSimon]

Griffin, thanks man for offering a hand. I might have to hit you up once I find a truck! Got pics of your 67 post tree attack? Im assuming it was the ice storm that dropped the tree?

67_c-30, Im very interested in all of the chatter, whether it pertains to my question or not, I have alot to learn....

[leddzepp]

Rust is your biggest enemy on these (or any car for that matter) trucks. Anything mechanical can be fixed. Body and paint work is the most expensive/time consuming/frustrating thing. Whatever truck you find, the less rust the better. If you lived in Calif, I could show you some great rust free trucks. And yes, there are trucks out there that still have the original rocker panels on them with no rust!

[67_C-30]

Originally Posted by JesseSimon

67_c-30, Im very interested in all of the chatter, whether it pertains to my question or not, I have alot to learn....

That's what we are here for! I'm fair (at best!) at body work, decent with general restoration, but engines are what I do best. I grew at race tracks with my dad as a kid, and until recently, I have raced since I was 14 years old. I have literally built just about every displacement small block and big block Chevy engine at one point or another for all kinds of applications - race and street. I'm a machinist by trade, so building engines according to tight tolerances and specs is something I love and am passionate about.

[JesseSimon]

Well C-30, Im gonna put you down as the guy to pester with engine questions if thats okay

[67_C-30]

Originally Posted by JesseSimon

Well C-30, Im gonna put you down as the guy to pester with engine questions if thats okay

Not a problem! Just give me a shout.

On your choice of truck, the biggest thing is to look around determine what you actually want. If you buy a LWB fleet and you really wanted SWB stepside, you are still going to want the SWB stepside. Trust me, I've tried that before.

Check out 1LOC10's photobucket site. It has 1000 pictures of 67-72 trucks. If I ever need a reference and I don't have it in my pic collection, I go here! Look through them a determine what you really want before a dollar.


http://s193.photobucket.com/albums/z...-72/?start=all

[JesseSimon]

That photo collection is just incredible

[67_C-30]

Originally Posted by JesseSimon

That photo collection is just incredible

Yes it is. He has been collecting for a while. Here's some more eyecandy for you in slide show form!

YouTube - Tribute to 67-72 Chevy/GMC Trucks

[Skirkpat]

Originally Posted by JesseSimon

What can you guys tell me about "double hump" heads? Im looking at another truck, the guy keeps talking about these heads...are they special?

Double hump heads used to be the hot setup before the aftermarket really stepped up and made cheap high performance heads, You can get more performance from aftermarket heads cheaper if you ask me, they are not even as good as Vortec heads if they are stock.

I would not get to giddy about them unless they have been ported and Polished, with a good 3 angle valve job.