Help me out guys. What is "low hump" and "high hump"? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Zumo · 08-05-2004, 01:33 PM

Low mean it's a 2wd and high mean 4wd?

dubie · 08-05-2004, 01:58 PM

Low humps were also in 2wd trucks that either had an auto tranny or a 3 speed. The high hump is only to make room for the 4 speed SM465 trannies and transfer cases on the 4x4 models. The high hump was basically used on every 4 speed truck

Zumo · 08-05-2004, 02:17 PM

So I can't put a 4 speed tranny in a low hump cab if I wanted? I guess I would have to ad a high hump right?

dubie · 08-05-2004, 02:22 PM

yep, cut a big ol hole in the floor and get a bolt on high hump for it. You can usually get them pretty cheap on the parts board. Or .....if I remember correctly, a Muncie 4 speed from an older Camaro would fit under a low hump. Might be worth checking into bud

Zumo · 08-05-2004, 02:46 PM

Thanks Doob. I would loave to have a 4 speed with a high a$$ shifter with a crazy Rat Rod shift knob on there.

dubie · 08-05-2004, 02:48 PM

Yeah they're cool. We converted the 3 speed column shift to a floor shift and it is going to have a fabricated rat rod shifter made up for it. This is what it looks like so far

Longhorn Man · 08-05-2004, 03:34 PM

The high hump was also on big block trucks with automatics..and it seems some of the 1500 GMC with V-6 engines and automatics came like this too.
This is a shot of my 69 1500 SWB GMC originally equipped with a 305 V-6 and TH400.

69ride · 08-05-2004, 06:57 PM

its a shame, I have a high hump in mine and only a auto tranny. there was a 4 speed in it

Hunter · 08-05-2004, 09:20 PM

Will the 700R4 tranny fit under a low humper? My truck has a high hump, but I'd swap it for a low one if the 700R4 will fit (future mod coming). H.

HOTFUN · 08-05-2004, 09:48 PM

Most turbo 400 automatic transmissions used the bolt in high hump floor pan. The exception that I have noticed is when the 400 was used behind the V6 GMC motor in 67. The low hump floor was just the standard floor stamping. When the 4 speeds, 4x4's, and most turbo 400 automatics were ordered, the factory stamp cut out the standard low floor pan and installed welded nuts in the underside floor so a bolt in/out high hump . Some reasons I suspect was is heat disapation clearance, some for access to the shifters. In my early GM master parts catalog you could buy a new cab in prime($900 back in 72) and one of the notes is cut floor for high hump installation and also for factory air installation, and others for harness modifications if I remember right. I'm not close to my books tonight but I am sure on the floor hump and the fact their was only one service cab part number coming from GM.
If your not a purist, just cut out the floor area and use no drill sheet metal screws and caulk and you'll have a factory looking cover installed in no time.
Mark

sub4rvr · 08-06-2004, 12:44 AM

Hey Longhorn Man, what's the small hole in your hi-hump for ?

Longhorn Man · 08-06-2004, 08:37 AM

I stopped trying to figure that one out sub4rvr. All I know is the hole has some original paint in it...so the hole has been there since day one.

Tx Firefighter · 08-06-2004, 09:13 AM

Hunter, yes you can easily put a 700 under a low hump floor. My orange truck is that way.

Also FYI to everybody, a big block and turbo 400 will also fit under a low hump floor, even though all of the factory big block/ auto trucks were high hump.

Ole Blue · 08-06-2004, 12:06 PM

Will a bb with a 700r4 fit under the low hump?

Tx Firefighter · 08-06-2004, 02:07 PM

Quote:

Originally Posted by Ole Blue

Will a bb with a 700r4 fit under the low hump?

Yes

67chevemall · 08-06-2004, 12:27 PM

Yep the 4 speed Muncie will fit under a low hump!
Looks better too!w/ low hump IMO!

08-05-2004, 01:33 PM	#1
Zumo Hot Rods For Life Join Date: Sep 2001 Location: Waxahachie, TX Posts: 3,305	Help me out guys. What is "low hump" and "high hump"? Low mean it's a 2wd and high mean 4wd? __________________ 1968 C10 LWB **SOLD* Andy Viva Los Bicicletas! Los Muertos Custom Bicycles

08-05-2004, 01:58 PM	#2
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	Low humps were also in 2wd trucks that either had an auto tranny or a 3 speed. The high hump is only to make room for the 4 speed SM465 trannies and transfer cases on the 4x4 models. The high hump was basically used on every 4 speed truck __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

08-05-2004, 02:17 PM	#3
Zumo Hot Rods For Life Join Date: Sep 2001 Location: Waxahachie, TX Posts: 3,305	So I can't put a 4 speed tranny in a low hump cab if I wanted? I guess I would have to ad a high hump right? __________________ 1968 C10 LWB **SOLD* Andy Viva Los Bicicletas! Los Muertos Custom Bicycles

08-05-2004, 02:22 PM	#4
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	yep, cut a big ol hole in the floor and get a bolt on high hump for it. You can usually get them pretty cheap on the parts board. Or .....if I remember correctly, a Muncie 4 speed from an older Camaro would fit under a low hump. Might be worth checking into bud __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

08-05-2004, 02:46 PM	#5
Zumo Hot Rods For Life Join Date: Sep 2001 Location: Waxahachie, TX Posts: 3,305	Thanks Doob. I would loave to have a 4 speed with a high a$$ shifter with a crazy Rat Rod shift knob on there. __________________ 1968 C10 LWB **SOLD* Andy Viva Los Bicicletas! Los Muertos Custom Bicycles

08-05-2004, 02:48 PM	#6
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,853	Yeah they're cool. We converted the 3 speed column shift to a floor shift and it is going to have a fabricated rat rod shifter made up for it. This is what it looks like so far Attached Images __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

08-05-2004, 03:34 PM	#7
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	The high hump was also on big block trucks with automatics..and it seems some of the 1500 GMC with V-6 engines and automatics came like this too. This is a shot of my 69 1500 SWB GMC originally equipped with a 305 V-6 and TH400. Attached Images

08-05-2004, 06:57 PM	#8
69ride All Go, No Show Join Date: Jul 2003 Location: Creighton SK Posts: 286	its a shame, I have a high hump in mine and only a auto tranny. there was a 4 speed in it __________________ 69 LWB Rebuilt 283, aluminum intake, edelbrock carb, Mild Melling Cam, HEI.

08-05-2004, 09:20 PM	#9
Hunter Lovin' Arizona Since 1961 Join Date: Jul 2004 Location: Camp Verde, Arizona Posts: 173	Will the 700R4 tranny fit under a low humper? My truck has a high hump, but I'd swap it for a low one if the 700R4 will fit (future mod coming). H. __________________ "Religion is like a toothbrush: Everybody should have one, but I don't want yours" - Will Rogers

08-05-2004, 09:48 PM	#10
HOTFUN Registered User Join Date: Jan 2001 Location: Lincoln, Nebraska Posts: 2,145	Most turbo 400 automatic transmissions used the bolt in high hump floor pan. The exception that I have noticed is when the 400 was used behind the V6 GMC motor in 67. The low hump floor was just the standard floor stamping. When the 4 speeds, 4x4's, and most turbo 400 automatics were ordered, the factory stamp cut out the standard low floor pan and installed welded nuts in the underside floor so a bolt in/out high hump . Some reasons I suspect was is heat disapation clearance, some for access to the shifters. In my early GM master parts catalog you could buy a new cab in prime($900 back in 72) and one of the notes is cut floor for high hump installation and also for factory air installation, and others for harness modifications if I remember right. I'm not close to my books tonight but I am sure on the floor hump and the fact their was only one service cab part number coming from GM. If your not a purist, just cut out the floor area and use no drill sheet metal screws and caulk and you'll have a factory looking cover installed in no time. Mark __________________ '66 CST BBW swb fleet 327 fac ac '67 CST 4x4 swb 327 stepside project '72 Cheyenne K20 50k original '72 Cheyenne Super K20 project '73 Sierra swb 4x4 frame off in paint stage '74 Cheyenne Super swb w/16k actual '71 & 72 Cheyenne K10 4x4 swb's '70 426 HEMICUDA conv SHAKER 4 sp Dana 60 '60 Impala conv 327 PG fac ac loaded 3rd owner '72 GMC K2500 4x4 '59 Apache CST BBW fleetside swb 283 '73 ElCamino SS LS1 T56 true SS bucket tach '76 ElCamino SS 52k survivor '87 Grand National 41k True 2nd to last built in 1987. '86 K30 454 SRW fleetside CA since new '88 Trans Am GTA 39k bought new 2018 DEMON plum crazy @ 840HP! "Need for speed"

08-06-2004, 12:44 AM	#11
sub4rvr Registered User Join Date: May 2000 Location: Palm Springs, Ca. Posts: 574	Hey Longhorn Man, what's the small hole in your hi-hump for ? __________________ 72 C10 Suburban 90 S10 57 F100 (2) 67 Mustang (2) 69 Torino GT 00 Mustang GT Conv.

08-06-2004, 08:37 AM	#12
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I stopped trying to figure that one out sub4rvr. All I know is the hole has some original paint in it...so the hole has been there since day one.

08-06-2004, 09:13 AM	#13
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Hunter, yes you can easily put a 700 under a low hump floor. My orange truck is that way. Also FYI to everybody, a big block and turbo 400 will also fit under a low hump floor, even though all of the factory big block/ auto trucks were high hump. __________________ I'm on the Instagram- @Gearhead_Kevin

08-06-2004, 12:06 PM	#14
Ole Blue Registered User Join Date: Sep 2003 Location: Holts Summit, Mo. Posts: 58	Will a bb with a 700r4 fit under the low hump?

08-06-2004, 12:27 PM	#16
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Yep the 4 speed Muncie will fit under a low hump! Looks better too!w/ low hump IMO!



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