looking at a 5th wheel that is 40 ft and 11000 lbs will (should) a 94 stock pull it ok? thinking of a pac brake, and gauges, I got 19.5 to put on the truck with 3.55 gears

 

Should pull fine. Don't expect to compete with a newer truck but at least you know you don't have emissions junk on it. I'd do some mild pump mods to boost you to 200 hp or so (like a #10 plate). Should pull much nicer, but keep an eye on the egt gauge.

 

I just pulled a 30' with a 10 plate 5 spd and 3.54 gears 4x4 and I would not recommend it. I pulled it up through the mountains and even with down shifting but still almost over heated the engine. I wouldn't pull anything but a 20ft goose behind a truck and maybe a 30'. Once you get that 40' trailer loaded it will put alot of stress on the truck even if it is a 1 ton.

 

I pull a 30' fiver that comes in at about 12600 loaded. Have a #5 plate with 15.5* timing and plate in stock location. Heats up a little on bigger grades, 6 or 7 percent for long distance, and I shift down. It depends on what RPM you can keep it at. If I manage to keep it above 1800 I don't have any problem and just cruise on up. If it drops below that due to traffic, then I down shift and let it go up slower. Just as long as you keep the RPM up you should be OK. Most drivers are not used to driving the Cummins at 2000 RPM and get nervous but it will do it with ease for as long as you need it to. Be nice to have 3.73 gears in it, good towing ratio.

 

A 40 foot fifth wheel isn't going to weigh 11K lbs.

 

This is what it is ,1987 Travel EZ 40' 5th Wheel they say that it weight is 11,000 lbs but i havent seen it yet triple axle