Changing Transmissions Humps

[BigHemi353]

I have a 86 4x4 with a high hump floor board and I want to put that floor in my 78 2wd cab with a low hump. I have searched and searched and come up with nothing so here is my question...... Can someone tell/show me where I need to cut this floor out so I can weld it into my 78 cab? Ive looked and measured but I still think Im going to screw they floor up if I start cutting. I only get one chance with this and want to make it count. Thank you, Andy

[Blazin]

Cut out the low hump first on the indentation thats there from the factory. Then cut out the high hump to fit. Cut the high hump bigger than you need, you can always trim it down a little at a time.
On the welding thing. I wouldn't weld it in. Leave the new piece about an inch bigger. Then screw it down with a ribbon sealant between the two.

[BigHemi353]

Thank you Blazin. I figured I was going to have to cut it out around the firewall and back to under the seat.

edit-
or will I have to cut the floor back farther? my hump continues back under the seat on my 86 4x4 cab and the 78 2wd cab ends right before the seat....im confused...

[dunedigger]

You can also get away with a body lift if you're not opposed to having one.  I believe a 2" kit will clear and you can save all the welding.

[BigHemi353]

I've considered that dunedigger but I have never been a fan of body lifts. Anyways, I already have a 6in. lift and already purchase my 35in tires.  I think 8in of lift and 35's might look a little funny. Kind of funny but I'm actually using your white 1980 as a role model for my truck except i went with 6in springs rather than 2in body and 4in suspension.

[dunedigger]

I personally don't like body lifts at all.  When I swap the frame out someday on my white truck I will pull mine.  Never again.

[BigHemi353]

I don't know why you don't like them DuneDigger but I just don't like their look. You see too much frame IMO. I'll take some pictures later today and post them on here to show what I'm talking about. Thanks guys

[BigHemi353]

Here is my high hump in my 86

Here is my low hump in my 78


What am I going to have to do? It looks the even the transition to the firewall is even different. The one on the 86 ribbed(crappy pic so you can't see it) going into the firewall and the 78's is not. I know now that I am going to have to cut back the 86's hump to the rear of the hump but what I'm worried about now is the front by the firewall.  Thanks guys

[BigHemi353]

I got bored and got the cutoff wheel out and cut it already. I cut back on the firewall and all the way back to the end of the hump. Believe it or not the year difference in the floors have a slightly different shape(basically the same) and fits a little different but I'll make it work

[Blazin]

Its not a picture perfect fit, but with a little hammer and dolly work they fit pretty good.

[BigHemi353]

Yeah, Its not going to be perfect but I'll be covered up with a full plastic molded floor mat so I'm not going to worry about it. At least i got what I needed from the 86 cab out and placed in the 78 cab.  Thanks guys

[Blazin]

When I do this I use the ribbon sealer meant to go in between the sheets of metal roofing on the long run where they over lap for a sealant. Over lap the new hump by about an 1 1/4" lay a strip or two of that down, then use self drilling / tapping screws with a 7/16" head and some washers. Pretty much any building supply place has that ribbon sealer in stock.

[BigHemi353]

Thanks Blazin. That was my original plan but I just didn't know what the ribbon sealer was called. I appreciate it!