4 speed hump cut out template. 1969 B body

[4mulas]

Any sight as the where to cut as the factory would have to install a 4 speed hump. I need to do this tomorrow and am not keen on pulling the carpet out of my other 4 speed car to look.

Thanks

 

[moparedtn]

There's a LOT of threads on this forum from other folks who have gone before you.
Use the search box in the upper right of any page and have a look.
Beyond that, the hump itself will tell you where it wants to go pretty much...

Thanks to the cut-outs and little notch in the bottom left, it pretty much plunks down where
it belongs.

 

[gkent]

Most of the factory cutouts were done with an axe or similar object. If you mark the floor around the outer edge of the hump and then cut a minimum of 1" inside that line you'll be as close to original as any factory hack job

 

[vintage chromoly]

The hump only sits in one spot.
As has already been said, trace it and move in an inch and cut.

Here are some pics

 

[vintage chromoly]

Also, I epoxied the hump down as opposed to welding it.
It has no structural element to it, and if anyone ever decides to convert the car back to an auto, it will be easier to patch.
I saved the cutout:

 

[gkent]

You don't have to cut so far back so as to expose the crossmember. Actually, a hole big enough for the shifter mechanism is sufficient. The rods are well below the floor.

 

[dsd1967]

If you look at Vintage Chromoloy's picture of the cutout exposing the cross member...you only have to cut the floorboard out to the cross member. It gains you nothing to go beyond because if there's going to be interference....the cross member will be the interfering part. By not going that far, it saves you from drilling spot welds, it prevents debris from getting into the cross member and it actually makes the cross member a little stronger by leaving the metal because it's "boxed" in.

 

[4mulas]

If you look at Vintage Chromoloy's picture of the cutout exposing the cross member...you only have to cut the floorboard out to the cross member. It gains you nothing to go beyond because if there's going to be interference....the cross member will be the interfering part. By not going that far, it saves you from drilling spot welds, it prevents debris from getting into the cross member and it actually makes the cross member a little stronger by leaving the metal because it's "boxed" in.

I am looking at this later today now and would have to agree with this logic 100%

 

[vintage chromoly]

Agree if you will, but original 4 speed cars are cut the way I did mine.

I just crawled all over and under an original sheetmetal 69 Roadrunner, and it’s done exactly like mine.

I doubt there is any significant structural component to 6 inches of sheet metal and 2 spot welds, but as has been said, there is no part of the shifter or rods that occupy that area above the crossmember. You will be left with a 3” or so “shelf” above the crossmember for stuff to accumulate. I prefer the open crossmember.

 

[gkent]

I have two and neither was cut that much. Just imagine some guy on the line drilling out those spot welds then making sure not to cut into the crossmember!! Not likely !!

 

[4mulas]

Agree if you will, but original 4 speed cars are cut the way I did mine.

I just crawled all over and under an original sheetmetal 69 Roadrunner, and it’s done exactly like mine.

I doubt there is any significant structural component to 6 inches of sheet metal and 2 spot welds, but as has been said, there is no part of the shifter or rods that occupy that area above the crossmember. You will be left with a 3” or so “shelf” above the crossmember for stuff to accumulate. I prefer the open crossmember.

You’re probably right, no stuctural significance. I’ll double check my factory 4 speed road runner again.

It likely depended on what day and what shift and who did from day to day. Probably none are done the same.

 

[eldubb440]

I've dealt with several..... the care in which the factory cuts the hole is less than impressive

 

[dadsbee]

Mine after blasting... definitely cut out above the cross member. Pretty sure we left it on the member when the new floor went in though.

 

[gkent]

I wonder if they were cut before the floors went in at the factory ?? I can't see them cutting above the crossmember on the assembly line, it just wouldn't make sense.

 

[vintage chromoly]

I thought I read somewhere that the earlier ones were cut on the line (and crudely so), but that later cars were punched before assembly.

I can say definitively that the 69 Roadrunner I looked at last week (unmolested original sheetmetal) was cut above the crossmember and was a clean cutout.

 

[vintage chromoly]

Maybe it was plant specific to some degree.
The RR is an A12, and as such, is a lynch road car

 

[4mulas]

I was wondering about this again this morning too, and agree with Stanton in that I can’t see them exercising such care to cut out above the cross member so carefully.

Maybe, they cut first then slipped the cross member in place and tack weld the cross member afterwards?

As Vintage said, I have seen some cuts that look like they were done with a sled hammer and dull tin snips but yet my road runner has nice clean cuts. My RR is a lynch road car.

As enthusiasts that own, love, and care for our cars as we do I’m sure we are often are too precise, overthink most things, and will exercise greater care and caution than anyone slapping these things together back in the day.

 

[4mulas]

I’m posting these in case it helps out others in the future. I didn’t cut above the cross member as I didn’t see any point in it. My other factory cut floor shifted 69 also did not cut above the crossmember. This yellow car was factory three in the tree, then Tremec 5 speed, now going to factory 4 speed

 

[4mulas]

 

[4mulas]

All welded in and seam sealed up.