Double Hump Heads on 350? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

OLDCHEV4X4 · 09-25-2002, 10:24 PM

Did double hump heads come on 350's from the factory? I say they did. Another guy says they didn't. 327 only. I have a set of double humpers with accesory holes in the ends that supposedly came off of a 1972 LT1. I have no proof. I need GM documation to win the bet.
Randy

adamls · 09-25-2002, 10:30 PM

Check out moretec.com. They have a good listing of casting numbers and where they came from.

bigjimzlll · 09-25-2002, 11:11 PM

yes they did come on 350s, but I think the ones on a lt1 in 72 were 487's..73 cc or 75cc chambers, not camel humps

Blazer1970 · 09-26-2002, 08:12 AM

The "real" camel hump heads were 461s, 462s and 291s. Both 461s and 462s were used on Camaro 350s in 1967. 291s were use on 350s in '68 and '69. These heads (on the 350 engines) all had the smaller 1.94/1.5 valves. The 186 castings have double humps and bolt holes (no bolt holes on 461, 462 or 291), and were used on the LT1 350 engines. The 186s on LT1s used 2.02/1.6 valves.

Beast388 · 09-26-2002, 10:50 AM

Don't forget about the #492 double hump castings that were only available over the GM parts counter. My buddy has a nice set of angle plug 492's that he won't part with.

6869704X4 · 09-26-2002, 02:28 PM

Mine are on a 69 300/350 out of an Impala. 194/150 valves. They have bracket holes in them. I have no reason to doubt that they didnt come on the engine. The guy I took the engine to for my first rebuild told me that all the parts on the engine were factory. Right down to the bearings. And if anybody would know he would. He has been building chevys since the late 50s. I know this isn't the GM documentation you need. That might be hard to find since GM didnt keep very good records.

meathead95 · 09-26-2002, 03:34 PM

the double humps on my s-10 are 461's and the have accessory holes.

OLDCHEV4X4 · 09-26-2002, 09:05 PM

My heads are 492's...So they were only available over the counter?? My small block casting number guide says"68-73 327-350 1.94 and 2.02 valves"...If the last 327 was made in 69 then there had to be some 350's with these heads....Right??? Now i need to find some GM documation.
Randy

ebfabman · 09-26-2002, 09:29 PM

meathead95, 461's with the accsessory holes???

Someone had to drill them. I could be wrong but the only double hump heads that I ever heard of or have ever seen that were on production motors with the accessory holes are 186's

You got pic of those heads?

bigjimzlll · 09-26-2002, 09:30 PM

any camel hump head made after 68 will have acc. holes

ebfabman · 09-26-2002, 09:38 PM

That wouldn't be 461's or 462's would it? I know 186's were '68's

bigjimzlll · 09-26-2002, 09:40 PM

3890462....66-67...302/327/350..Camel hump,no accessory holes,64cc chamber
3901068....87-up...350..........Crate motor, 285hp, 64cc chamber
3911032....68......307/327......70cc chamber
3912264....58-62...283
3912265....63-64...283
3912311....65-67...327
3912313....65-67...327
3917290....67-68...307/327
3917291....67-68...302/327/350..Camel hump,no accessory holes,64cc chamber
3917292....68......327/350......Camel hump,64cc chamber
3917293....68......307/327......75cc chambers
3927185....69-76...307/327/350..70cc chambers
3927186....69-70...302/350......Camel hump,64cc chambers,accessory holes
3927187
3782461....64-66...327......Camel hump,no accessory holes,160/62cc port volumes,62cc chamber
3782461X...60-63...283/327..Camel hump,no accessory holes,larger 172/64cc port volumes, 62cc chamber
3795896....

ebfabman · 09-26-2002, 09:42 PM

461's and 462's were prior to 68 and had no accessory holes

OLDCHEV4X4 · 09-26-2002, 09:42 PM

efabman, so my 492 heads with accessory holes didnt come on a production motor?

ebfabman · 09-26-2002, 09:47 PM

492's were after 68 and had the holes, like 186's

ebfabman · 09-26-2002, 09:49 PM

oh, you said production motors, I think the 492's were over the counter only.

crazy longhorn · 09-26-2002, 09:50 PM

I didnt see the 492s listed in in that group of castings,but i ran a set that were straight plug castings,& it was my understanding that they were Z28/Lt1 factory castings.

OLDCHEV4X4 · 09-26-2002, 09:56 PM

Crazy longhorn, So they came on a 350 LT1 from the factory. You wouldn't happen to have any documation on that , would you? There's no money on the line for this bet. Just the gratifaction of saying "I fu___ng told you so!"
Thanks,, Randy

crazy longhorn · 09-26-2002, 10:06 PM

No, i sure dont have any documentation,just stretching my memory on what i was told several years ago. Mine were straight plug heads,but i think any of the angle plug heads were over counter only........i dont want to place any bets tho,its been a while since i played with the old stuff!

Fred T · 09-26-2002, 10:18 PM

The heads on my 350 are 3932454 with two square humps. Anyone know what they are? Mortech is pretty generic, 68-79 307 or 350.

Beast388 · 09-26-2002, 11:58 PM

OLDCHEV4X4's comments got me thinkin'...........so I dug out my book to verify my previous post. This is what Small Block Chevy Performance by Dave Emanuel has to say about 492 castings: "In the early seventies, 492 castings were available with angle spark plug holes, but this version, part no. 336746, was offererd for a very short time, and only through the Chevrolet parts department; angle-plug 492 castings were never factory installed on a production engine."

So it sounds like straight plug 492's could come on a factory engine but angle plug 492's were only available over the counter. So I'm only half right.

meathead95 · 09-27-2002, 07:30 AM

ebfab i will get a pic tomorrow

*big71* · 09-27-2002, 07:39 AM

i got a set of 492 and these 14011034 whice is bowtie whice do ya thank are better iam planning to bulid a motor in the neaxt mounth so thanks

Blazer1970 · 09-27-2002, 07:52 AM

My book lists 492s as service only. As you can see from the responses to this, it is hard to 100% pin down what was used and when. It seems pretty clear to me that 462 double humps were used on Camaro 350s in 1967 though, which answers your question. Not sure what proof your friend would want to see though. Find someone with a stock '67 Camaro with a 350, I guess.

bigjimzlll · 09-27-2002, 09:01 AM

there are several..I think 3..reincarnations of the 034 bowties.. A nice head, they out flow camel humps and have real thick castings

09-25-2002, 10:24 PM	#1
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	Double Hump Heads on 350? Did double hump heads come on 350's from the factory? I say they did. Another guy says they didn't. 327 only. I have a set of double humpers with accesory holes in the ends that supposedly came off of a 1972 LT1. I have no proof. I need GM documation to win the bet. Randy __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

09-25-2002, 10:30 PM	#2
adamls Gotta Startem Early Join Date: Oct 2001 Location: Amarillo, TX, USA Posts: 364	Check out moretec.com. They have a good listing of casting numbers and where they came from. __________________ 67 SWB In Progress, one piece at a time, maybe 3 years I will be finished

09-25-2002, 11:11 PM	#3
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	yes they did come on 350s, but I think the ones on a lt1 in 72 were 487's..73 cc or 75cc chambers, not camel humps __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

09-26-2002, 10:50 AM	#5
Beast388 Suburbans RULE! Join Date: Jan 2000 Location: Clinton, IA 52732 Posts: 689	Don't forget about the #492 double hump castings that were only available over the GM parts counter. My buddy has a nice set of angle plug 492's that he won't part with. __________________ --Ben 71 GMC Suburban 4X4 The "Beast" 388 CID Stroker, TH350, NP205, 8-lug D44, 14BFF w/ Detroit, 4.10:1 gears, 4-Wheel Disks 4" Lift, 35" MT/R's.

09-26-2002, 02:28 PM	#6
6869704X4 Registered User Join Date: Jul 2002 Location: SE NM Posts: 769	Mine are on a 69 300/350 out of an Impala. 194/150 valves. They have bracket holes in them. I have no reason to doubt that they didnt come on the engine. The guy I took the engine to for my first rebuild told me that all the parts on the engine were factory. Right down to the bearings. And if anybody would know he would. He has been building chevys since the late 50s. I know this isn't the GM documentation you need. That might be hard to find since GM didnt keep very good records. __________________ The more I learn about women, the more I love my truck.

09-26-2002, 08:12 AM	#4
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	The "real" camel hump heads were 461s, 462s and 291s. Both 461s and 462s were used on Camaro 350s in 1967. 291s were use on 350s in '68 and '69. These heads (on the 350 engines) all had the smaller 1.94/1.5 valves. The 186 castings have double humps and bolt holes (no bolt holes on 461, 462 or 291), and were used on the LT1 350 engines. The 186s on LT1s used 2.02/1.6 valves. __________________ Tim

09-26-2002, 03:34 PM	#7
meathead95 computer illiterate Join Date: Jan 2001 Location: Des Moines, IA Posts: 6,446	the double humps on my s-10 are 461's and the have accessory holes. __________________ 72 2wd blazer 72 swb 4x4

09-26-2002, 09:05 PM	#8
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	My heads are 492's...So they were only available over the counter?? My small block casting number guide says"68-73 327-350 1.94 and 2.02 valves"...If the last 327 was made in 69 then there had to be some 350's with these heads....Right??? Now i need to find some GM documation. Randy __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

09-26-2002, 09:29 PM	#9
ebfabman Registered User Join Date: Nov 2001 Location: Concord, NC Posts: 2,489	meathead95, 461's with the accsessory holes??? Someone had to drill them. I could be wrong but the only double hump heads that I ever heard of or have ever seen that were on production motors with the accessory holes are 186's You got pic of those heads?

09-26-2002, 09:30 PM	#10
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	any camel hump head made after 68 will have acc. holes __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

09-26-2002, 09:38 PM	#11
ebfabman Registered User Join Date: Nov 2001 Location: Concord, NC Posts: 2,489	That wouldn't be 461's or 462's would it? I know 186's were '68's

09-26-2002, 09:40 PM	#12
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	3890462....66-67...302/327/350..Camel hump,no accessory holes,64cc chamber 3901068....87-up...350..........Crate motor, 285hp, 64cc chamber 3911032....68......307/327......70cc chamber 3912264....58-62...283 3912265....63-64...283 3912311....65-67...327 3912313....65-67...327 3917290....67-68...307/327 3917291....67-68...302/327/350..Camel hump,no accessory holes,64cc chamber 3917292....68......327/350......Camel hump,64cc chamber 3917293....68......307/327......75cc chambers 3927185....69-76...307/327/350..70cc chambers 3927186....69-70...302/350......Camel hump,64cc chambers,accessory holes 3927187 3782461....64-66...327......Camel hump,no accessory holes,160/62cc port volumes,62cc chamber 3782461X...60-63...283/327..Camel hump,no accessory holes,larger 172/64cc port volumes, 62cc chamber 3795896.... __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA Last edited by bigjimzlll; 09-26-2002 at 09:42 PM.*

09-26-2002, 09:42 PM	#13
ebfabman Registered User Join Date: Nov 2001 Location: Concord, NC Posts: 2,489	461's and 462's were prior to 68 and had no accessory holes

09-26-2002, 09:47 PM	#15
ebfabman Registered User Join Date: Nov 2001 Location: Concord, NC Posts: 2,489	492's were after 68 and had the holes, like 186's

09-26-2002, 09:49 PM	#16
ebfabman Registered User Join Date: Nov 2001 Location: Concord, NC Posts: 2,489	oh, you said production motors, I think the 492's were over the counter only.



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09-26-2002, 09:50 PM	#17
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	I didnt see the 492s listed in in that group of castings,but i ran a set that were straight plug castings,& it was my understanding that they were Z28/Lt1 factory castings.

09-26-2002, 09:56 PM	#18
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	Crazy longhorn, So they came on a 350 LT1 from the factory. You wouldn't happen to have any documation on that , would you? There's no money on the line for this bet. Just the gratifaction of saying "I fu___ng told you so!" Thanks,, Randy __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

09-26-2002, 10:06 PM	#19
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	No, i sure dont have any documentation,just stretching my memory on what i was told several years ago. Mine were straight plug heads,but i think any of the angle plug heads were over counter only........i dont want to place any bets tho,its been a while since i played with the old stuff!

09-26-2002, 10:18 PM	#20
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	The heads on my 350 are 3932454 with two square humps. Anyone know what they are? Mortech is pretty generic, 68-79 307 or 350. __________________ Fred There is no such thing as too much cam...just not enough engine.

09-26-2002, 11:58 PM	#21
Beast388 Suburbans RULE! Join Date: Jan 2000 Location: Clinton, IA 52732 Posts: 689	OLDCHEV4X4's comments got me thinkin'...........so I dug out my book to verify my previous post. This is what Small Block Chevy Performance by Dave Emanuel has to say about 492 castings: "In the early seventies, 492 castings were available with angle spark plug holes, but this version, part no. 336746, was offererd for a very short time, and only through the Chevrolet parts department; angle-plug 492 castings were never factory installed on a production engine." So it sounds like straight plug 492's could come on a factory engine but angle plug 492's were only available over the counter. So I'm only half right. __________________ --Ben 71 GMC Suburban 4X4 The "Beast" 388 CID Stroker, TH350, NP205, 8-lug D44, 14BFF w/ Detroit, 4.10:1 gears, 4-Wheel Disks 4" Lift, 35" MT/R's.

09-27-2002, 07:30 AM	#22
meathead95 computer illiterate Join Date: Jan 2001 Location: Des Moines, IA Posts: 6,446	ebfab i will get a pic tomorrow __________________ 72 2wd blazer 72 swb 4x4

09-27-2002, 07:39 AM	#23
big71 Account Suspended Join Date: Nov 2001 Location: JONESVILL NC Posts: 1,303	i got a set of 492 and these 14011034 whice is bowtie whice do ya thank are better iam planning to bulid a motor in the neaxt mounth so thanks

09-27-2002, 07:52 AM	#24
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,510	My book lists 492s as service only. As you can see from the responses to this, it is hard to 100% pin down what was used and when. It seems pretty clear to me that 462 double humps were used on Camaro 350s in 1967 though, which answers your question. Not sure what proof your friend would want to see though. Find someone with a stock '67 Camaro with a 350, I guess. __________________ Tim

09-27-2002, 09:01 AM	#25
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	there are several..I think 3..reincarnations of the 034 bowties.. A nice head, they out flow camel humps and have real thick castings __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

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