crewcab hump

[crewcabshorty]

I have a1988 crewcab with a sm465 trans , i want to swap in anv 4500 . I took out the floor mat and the hump does not unbolt . do i need to cut the hump out to pull the tranny or is there room without the cut ?

[v30crewcab]

just take it out the bottom. it'll work fine. I pull my nv4500 out the bottom and my truck was an automatic. the sm465 has a bigger hump.

[arrover]

v30crewcab, How well does the NV4500 fit in your truck with the auto floor pan? Do you have to run a body lift and if so, how large? My eventual goal is to run NV4500 behind a cummins in a crew cab like you. Up till now I thought I needed a high hump cab (or splice a high hump into an auto cab).

[my4by2]

Not sure why your hump wouldn't come out - the one in my '77 does... You will need to modify the shifter locations a bit going from the SM465 to an NV4500 - this is the exact swap we did with my truck.

[v30crewcab]

somewhere around 80 they quit bolting the floorpan humps in.
my trans fits fine, no bodylift. but the shifter stub does stick up thru the floor some.
I wouldn't mind putting a bolt in hump in mine, but my carpet is fairly new, and I don't feel like buying carpet again for awhile.
I'd take a pic but my cab is off the frame at the moment.

[Desert1957]

I think its more than just the removable center section. I have looked at both my trucks and the surrounding floor pans around the shifter are bent at a different angle to support the cover.

Desert

My 83 still has a removable floor.

[v30crewcab]

interesting. my 84 stickshift did not have a removeable cover.

[yousesteers]

My 84 crew did not have a removable hump but some one before my torched around the hump and made it removable. I am running a NV4500 behind my cummins with no problem and i am not running any lift on the truck. It was originally a 350/sm465 combo

[Desert1957]

Originally Posted by Desert1957

I think its more than just the removable center section. I have looked at both my trucks and the surrounding floor pans around the shifter are bent at a different angle to support the cover.

Desert

My 83 still has a removable floor.

Its a "Camper Special" I wonder if that's the reason?


Desert

[esbstuff]

83 was the last year for the removable hump, at least offically that is... I can see GM using left over floor pans into 84 or using 83's till they were gone into the 84 model year... Its make no differace on trim/option level.

BTW it was a cost savings measure... GM saved $5 (?) by not making the pan removable... But transmission change time was not increased because if you figured in correctly removing the seat and carpet to remove the removable hump correctly there was no net time change.

Just to cover the bases here...

The short hump was for automatic and 3 speed manual 4x2's, the medium hump was for 4-speed manual 4x2 (as shown in the brown truck above, see the hump taper back as it goes under the seat ) and the tall hump was for 4x4 either auto or manual. In the 73-83 trucks the 4 speed hole was a knock out hole in the 4x4's, in 84 that was made as a single piece that needed cut out. BUT all trucks had the dimples for the correct screw location, go figure. Also the 3-speed manual (not the floor shift 3 speed with granny low, but a real 3 speed on the column) 4x4's also used the tall hump but this option was not very popular and is super rare today. I have only heard of one and have a 73 GM master book that shows it as an option.

I will also note that medium humps and tall humps are not completely inchangeable when they are bolt-ins. The medium hump is shorter in the back by almost 3 inches. The bolts on the front and the sides are in the same place though.

---The brown truck above is shown with the incorrect shifter boot, but if my memory serves me correct, the boots are the same screw pattern---All 81-91's had the square boot, but otherwise appears to be a nice truck.

[Desert1957]

Originally Posted by esbstuff

---The brown truck above is shown with the incorrect shifter boot, but if my memory serves me correct, the boots are the same screw pattern---All 81-91's had the square boot, but otherwise appears to be a nice truck.

Sorry, But the boot IS the original GM part, I have known this truck since new. I have performed ALL the maintenance and it was a 1 owner , little old man special.

Desert

[motornut]

Originally Posted by esbstuff

83 was the last year for the removable hump, at least offically that is... I can see GM using left over floor pans into 84 or using 83's till they were gone into the 84 model year... Its make no differace on trim/option level.

BTW it was a cost savings measure... GM saved $5 (?) by not making the pan removable... But transmission change time was not increased because if you figured in correctly removing the seat and carpet to remove the removable hump correctly there was no net time change.

Just to cover the bases here...

The short hump was for automatic and 3 speed manual 4x2's, the medium hump was for 4-speed manual 4x2 (as shown in the brown truck above, see the hump taper back as it goes under the seat ) and the tall hump was for 4x4 either auto or manual. In the 73-83 trucks the 4 speed hole was a knock out hole in the 4x4's, in 84 that was made as a single piece that needed cut out. BUT all trucks had the dimples for the correct screw location, go figure. Also the 3-speed manual (not the floor shift 3 speed with granny low, but a real 3 speed on the column) 4x4's also used the tall hump but this option was not very popular and is super rare today. I have only heard of one and have a 73 GM master book that shows it as an option.

I will also note that medium humps and tall humps are not completely inchangeable when they are bolt-ins. The medium hump is shorter in the back by almost 3 inches. The bolts on the front and the sides are in the same place though.

---The brown truck above is shown with the incorrect shifter boot, but if my memory serves me correct, the boots are the same screw pattern---All 81-91's had the square boot, but otherwise appears to be a nice truck.

does all that apply with the Jimmy/Blazer,Suburban platform as well?

[esbstuff]

Originally Posted by Desert1957

Sorry, But the boot IS the original GM part, I have known this truck since new. I have performed ALL the maintenance and it was a 1 owner , little old man special.

Desert

I have parted out over 500 73-91 trucks and have never seen a round boot in a 81-91 truck that was factory.

Maybe keith can way in on this issue...

[esbstuff]

Originally Posted by motornut

does all that apply with the Jimmy/Blazer,Suburban platform as well?

Yes I believe so. My knowledge on Blazer/Suburbans are a little thin as I have not parted as many of those out.

[v30crewcab]

I'll have to go look, but I'm pretty sure my 84 gmc has that same shifter boot.

[Desert1957]

Originally Posted by Desert1957

Sorry, But the boot IS the original GM part, I have known this truck since new. I have performed ALL the maintenance and it was a 1 owner , little old man special.

Desert

Originally Posted by esbstuff

I have parted out over 500 73-91 trucks and have never seen a round boot in a 81-91 truck that was factory.

Maybe keith can way in on this issue...

Here is an old pic of my 77 Dually / SM465 bone stock with a round boot.



Desert