Hi all, my name is Roy and i am new to the forums. I will be up front and say i dont know much about engines and such except a few basics. My dad use to have a body shop that i worked in when i was young so i was always looking in that direction. I teach school now and recently decided to get me a truck

. I had one 10 years back but it got totalled by a friend and i lost my baby.
Well i started looking this past Feburary and in May i found my beauty. I couldnt pass it up at 2200 so i bought this '86 K10 4X4. I knew the guy who had it and put it together for his son (one of my former students). So i knew the history of it, but it was sold to another person who kept it for a little over a year so there is some time of not knowing what was done. He couldnt afford to drive it anymore due to gas and needed money for a smaller car so i jumped on it.
It has had alot of work put into it, including new Midnight Black paint, true GM bed, doors and right fender, and interior. So very little to no rust. The 305 was replaced with a 350 crated motor with around 40k (a year of undocumented mileage) and custome duel exhaust. My kids at school loveeeee it

. They call it "The Beast" cause it is the oldest vechile on our school lot in the morning.
I have done some work on the motor and had some done at my mechanic ( the guy who put it together for his son.) I replaced the intake with an Alum torker but i kept the original 4B that was on it (Qjet...i have heard the Q are all 800cfm ...it that true?) I rebuilt the 4B, new plugs, 190 thermo, fuel pump, wires.
This is my problem i will describe, maybe someone has a suggestion to look for or inquire about. I think it is the tranny but i am not for sure due to me rebuilding the 4B

.
First the tranny is suppose to be a overdrive and i had a transmission guy tell me it was one. Now with it being a overdrive and i am looking at the column shift it goes from OD, D, 2, then boom no 1 where there should be (column has that gear on it). If i am at a rolling stop or stopped this thing will squall the tires, up to around 50-60 mph. But if i am out driving 55 or so and go to pass someone it seems the passing gear is not kicking in, i cant even feel the 4B kick in. It just kinda farts around the car (embarrassing). Now with it not being able to go into low 1 I am wondering if there is a linkage problem to look at ( and is this something that would require pullin the tranny?) I have adjusted the slide for the tranny on the carb (pushing the button and sliding the black piece all the way in then pressing down on the peddle ...like i said i know little about some of the engine terms and such

) I was told this would reset it to factory but it still acts the same. Ohhh it has 3.08 gears that i want to change(factory)...could this be the problem for high end sluggish behavior?
This is things i am thinking. I called Jegs and was told to put a holley 570 on it so i am thinking that route. (they said the Quadjet was too much CFM...is this true?)
The tranny guy said the tranny didnt need rebuilt but he could put a different servo in it to make the 1st to 2nd more crisp. Is this a good idea?
Gear replacement to 3.73, im not worried bout lost gasmileage. This truck is going to be a toy.
Thanks for any input if you can make heads and tails of my blabber. Look forward to learning some things i always wanted to but never had time or money before to.
Also would anyone know if having a Rhino bed sprayed in it would lower the value of it, since it is considered a Classic?