small or big hump and tranny question

[corvettejim1968]

do i have a small or big hump 1965 c10 230 strait six born with a powerglide now has a 350TH. and do you think a 4L85E tranny will fit?

also does anybody know what the large spring is for? i know the small one is for my jack. thank you

[rossboss]

I believe the large spring holds the lug wrench and jack handle down.

[markeb01]

Can't help with the floor question, but the long spring is for retaining the jack handle and lug wrench. Posts #4 & 13 include diagrams showing the layout:

http://67-72chevytrucks.com/vboard/s...t=factory+jack

Just read you question again - you definitely have the small hump. I just don't know if the 4L85E trans will fit. Here is a picture of a high hump. The pan is almost square in the center, rises up in front of the seat, and is always removable:



The low hump drops in front of the seat, may be removable or may be a permanent part of the floor. From all the threads I’ve read on this topic, they are not directly interchangeable, however a high hump can be added to a low hump truck if the portion from the high hump donor truck in front of the removable pan is also cut out and welded into the low hump cab.

[CRGRS 66]

That looks like a small hump to me, the big humps are BIG, usually 4x4's. The spring I believe is the hold down for the factory jack, not 100% certain of that, but that is my guess.

[CRGRS 66]

If you dig around on here you will see some big humps

[rideblue00]

CRGRS66 beat me to it, lol. Yeah the big hump you would know if you have it. The hump you have under your seat there...its the same on all trucks. Its the part of the floor thats in front of that. A 4 speed truck floor, is way taller between the firewall and the seat. Powerglide and 3 speed trucks have your floor. The 66 year had the turbo 400 availible and it also has the same floor as yours. I dont have a pic handy. But i have a big hump with a 4 speed SM420 trans. 4 speed floors are also removable. There is a legend out there about the early trucks that had a removable small hump, but i havent seen pics of it. Im not sure on the fit of the newer trans, but the 700r4 supposedly just bumps the floor pan seam that runs side to side, like where your feet go, and some guys just peen it over near where it touches.

[ABX131]

You have a small hump. The large hump will line up flush to that rolled seam you have near the edge and extend about 4 inches past the end of your existing floor cover. If you find someone parting out a truck with a large hump, make sure you get the 2nd piece that is spot welded to the tranny tunnel. This is needed or you will have a gap between the end of the hump and the firewall.

[rideblue00]

Good call ABX131, i forgot to mention that.

[rideblue00]

Heres a high hump. This is from a fellow member(rossboss). I hope he doesnt mind.

[KVB]

Will a 700R4 fit under the low hump?

[gimmy 64]

had a 350 now 2004r low hump and both fit fine. no altering at all

[rideblue00]

I heard that the low hump will just touch on the 700R4 on the floorpan seam where it connects to the firewall(sidetoside seam) .

[sigshooter]

Originally Posted by rideblue00

CRGRS66 beat me to it, lol. Yeah the big hump you would know if you have it. The hump you have under your seat there...its the same on all trucks. Its the part of the floor thats in front of that. A 4 speed truck floor, is way taller between the firewall and the seat. Powerglide and 3 speed trucks have your floor. The 66 year had the turbo 400 availible and it also has the same floor as yours. I dont have a pic handy. But i have a big hump with a 4 speed SM420 trans. 4 speed floors are also removable. There is a legend out there about the early trucks that had a removable small hump, but i havent seen pics of it. Im not sure on the fit of the newer trans, but the 700r4 supposedly just bumps the floor pan seam that runs side to side, like where your feet go, and some guys just peen it over near where it touches.

I have only seen the removeable LOW hump in 1963 trucks.... I pulled one a few weeks back for one of my trucks out of the scrap yard I work in..... There is one in a 63 at Cagles Salvage in Muskogee Oklahoma also..... A friend of mine has one in his 63 parts truck, that is the only three I personally know of left around here

[rideblue00]

If you get time, post a picture. Either of the cab floor or the hump itself. Ive never seen one.

[cru_zn_29]

I have a small hump 66 swb with a 4L60E it clears. i think the 4L80E is larger and will need the large hump.kenny

[markeb01]

Originally Posted by rideblue00

If you get time, post a picture. Either of the cab floor or the hump itself. Ive never seen one.

Here are a couple of pictures of a removable low hump. No idea what year truck it came from:

[Trap62]

Mine looks like that. 1962 SWB BBW side step built in the Los Angeles plant.
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[sigshooter]

Originally Posted by markeb01

Here are a couple of pictures of a removable low hump. No idea what year truck it came from:

That is it.... They may have come on several or every year, I don't know. I have been messing with these trucks for 25 years and have personally only seen a handful and all have been on the 1963 models. I have never personally seen one on a 456 model.

Anyone else have more info on the bolt in low hump?

[rideblue00]

Wow, thats cool! Never seen that before. Any reason they might do that in the early trucks and not 456 years?

[Heater63]

Mine has the picture sigshooter posted. It is '63 Short Step built in St Louis with a 230/3 on the tree.

[Dino Driver]

I'm putting a 4L80 in my 1960. The 60 cab I have has the removable high hump but I have a weld in low hump that I'm going to try really hard to use. It will be a while until I get there, I hope you have good results!

[Trap62]

These shots are of my 1962 removable small hump.

[Heater63]

Wow Trap, nice low rust original floor/cab! No patch panels, even the rockers are original?! Rarely see that anymore!

[Rusty one]

Dam,that floor is clean & rust free!!!