Where's the difference?

[Phantom440]

Hey all, I hope you're doing well!
Quick question; this pertains to a '71-up B-body.
The '71 Charger wheelbase is 115".
The '71 Coronet wheelbase is 118".
Where are those three inches located on the car? (in before "between the wheels" comments)
The reason I ask is I bought a set of subframe connectors for a '71 Charger, and talking with the guy from US Car Tool, he said that the connectors should work, that he'd installed connectors on earlier B four doors before, but never on a '71-up. I just did a hand fit against my floorboard, and they're close, but they are too short.
Now looking into the measurements, it seems pre-'71, 2 and 4 door B's had the same wheelbase.
What would be the best course of action? Maybe getting the connectors lengthened? Could I just add the 3" to one end and it'd work, or is that 3" spaced incrementally throughout the wheelbase and I'd have to chop the connectors up into 9 pieces to add an inch here, and inch there, etc?
Sidenote, anybody want a pair of US Car Tool '71 Charger subframe connectors in exchange for making custom ones for me?

 

[67 coronet]

should be easy to tell.line up the rear section of the connector and measure the distance you have left in front.

 

[Phantom440]

That's a good idea, I'll try it. My only concern is these connectors have the contours to follow the floorpan, so if the floorpans are different, the entire thing may not match up. I've only done a quick fitting, I may have just been holding it up wrong and it'll fit just fine... but if someone knew "yeah, there's an inch longer in the rear footwell, then half an inch between the front subframe and the front floorboard, then 1.5 inches under the front seat" or something, I'd have to hack up the ones I have in multiple places to lengthen it appropriately.
Sort of related, what are everyone's thoughts on the connectors that fit exactly against the floorpan vs. square tubing?

 

[67 coronet]

you are just trying to connect the two frame sections together.as long as the strength is the same it does not matter what you use.if you are trying to weld the but up connector to the floor board, then you might want to think about a full tube chassis instead.because you must be putting some monster power to the ground to need that.

 

[Phantom440]

Hahahaha, not at all! Right now I just have a warmed over 318. (Though a 440 is in the plans.)
I'm building the car for some light stunt work in a movie and just want to tighten up/strengthen the unibody where I can. I'll see if I can figure out some square tubing solution. Thank you!