COE Sleeper/rear seating area length? How much room is enough?

I now have a kid and my original plans for regular cab trucks that I have are changing. I am wanting/needing to add a sleeper to my 55 Chevy LCF. I am not going to try to build another Big Bertha, that is too much time and effort to realistically put on my plate. A big box on the other hand, I can probably make happen.

What I want to accomplish is to make a rear seat and I want to make it comfortable for adults to set back there as well so I am wanting to know if anyone here has their truck with sleeper in use and how long or deep the sleeper is. Is 36" deep enough for long drives? This truck is going to be the hauler and we will use it for 5+ hour trips one way if not longer. It will probably get a seat out of a newer truck, what ever I find at the salvage that is nice, not sure if they tend to be thicker seat backs or not.

I have not worked through whether the back of the cab needs to be removed or if logistically it will be fine to take the rear gl*** out and have a p*** through. The rear window opening is pretty small and trying to communicate with a kid back there through it may be a pipe dream.

Thanks,
Jason

 

Jason, I just walked out to my garage and sat in the back seat of a Toyota Camry that is about 5 years old. It is comfortable for me @5'9" 180 lbs. It is 34" from back of seat to back of front seat, you would have to add the thickness of your seatback to this. I'd plan in the 42" range for total room, unless you consider sitting crosswise.
I have a 36" sleeper, but it is strictly a lay-down bunk with no provision for sitting up. (engine under it)
Trust me, there will be a day when you will want to backhand the kid while driving, difficult through a window opening!
BTW, I knew a guy that drove many hours with an adult son and his girlfriend behind the seat (on a beanbag) in a 39 Ford coupe. I'd have told daddy to shove it!

 

Thanks Steve, I have been trying to draw it up and get an idea as to proportions. The more I think about it, the 42" would probably be the minimum for comfort.

I rode in the back of my SIL's Saturn SC2 for 3+hrs one time. It was like setting in a 5 gal bucket with a pc of gl*** on top of my head. The seat bottoms were so deep that I couldn't turn sideways any easier than setting forward facing, and the back gl*** was right on my head. I am the same height as you. Terrible back seat but got 44 mpg.

Also the more I think about actually building a proper sleeper box and getting the transition from cab to sleeper right and have a door on it with windows, I may be in it the same level of work as doubling the cab.

I have an 18' box that I thought about putting on it for RV type use, it may make sense to just permanent mount it and have transport seats in it, not worry about putting extra people in the cab. I am complicating it by putting the engine behind the cab as it is a 9.0L IH v8, just won't fit up front. I need to decide though as I hope to actually start working on it this year and the engine placement will be determined by the cab situation...

 

BTW, I do have pictures of how I built my sleeper.
The ultimate sleeper for yours would be a Mercury, but difficult to find and expensive if you find a good one.
With modern video cams one could build an interactive system between a camper box and the cab, so the kids wouldn't be too isolated and a doghouse in the front of the camper could be tolerated if it sealed out engine and road smells. Vans have been this way for many years.
Mercury sleepers were wood framed (I think) and tended to shake/rot apart over time, but damn they looked good.

The frame of mine

 

I think my plans have taken a turn. My Plan for this truck for the almost decade I have had it was to put the cab on an old bus ch***is. The bus runs and drives, it is an 84 IH with a 9.0L v8 diesel in it. It of course is larger track width than the 55, I had come up with a plan to deal with that which included putting the engine behind the cab as it is just physically too big to fit. It also would have to have the front axle narrowed and all the stuff to go with that. The list was not insurmountable, but long and realistically probably too much for the forseeable future to get done.

Working through the sleeper/back seat arrangement has forced me to rethink things. I have a 1970 C50 that I am thinking will go on the bus ch***is instead of the 55. Doing this will allow the bus ch***is and drivetrain to stay in stock location and the newer cab is wider and also already has stock fender extensions which could be made wider if needed. Then a sleeper could be potentially bought and installed with alot less work due to the shape of the cab and such. I also wouldn't have to deal with an engine under it and such.

Then the 55 would stay factory bodywork, probably put a sbc in it as it will bolt in and I have a running one. Update axles and drive it.

 

That sounds too easy!
I know how it goes. Mine started out going on a Dodge motorhome ch***is as a ramp truck with a 440 gas job, then an Isuzu ch***is with a ***mins as a toter and now IH frame rails with full custom suspension and a Detroit diesel. (no sleeper on the first 2) It was supposed to be a 5 year project. (17 years ago) Time flies when you are having fun!

 

I know, the more I think on it, the easier the c50 cab will be.

Having a kid really monkey's up plans

 

My sleeper is a 36" Pete. I did the same mental gymnastics on usable rear seat space that you are... The 36" gives acceptable front to back room. Pretty much the same deal as most vehicles, if a taller person is in the back seat, the front seat needs to move forward a bit. The full cutout between cab and sleeper allows the rear p***enger's feet under the front seat area. The only thing missing in my setup is footwell depth. The rear seat has next to none since the motor is under the sleeper. A motor placed up front would eliminate this issue.