Misfire/hesitation under acceleration.
 

My truck which I purchased about a moth ago is having issues with acceleration it will almost stall when it to the floor accelerating. If I baby it it'll accelerate fine. Wearable's have been replaced cap and rotor plug wires, vacuum line etc any ideas?

Welcome to FTE Elmer

With the engine off, shine a flashlight down the carburetor throat and wing the throttle. Should see two thin streams of fuel squirt. This compensates for the temporary lean out when accelerating.

In addition to what Tedster said, did you also replace the spark plugs themselves? If so, what did you gap them at? You said wires, but not plugs specifically, so I wanted to make sure.

And so I don't have to go click on your information, what year and model is the truck, and which engine? Along with, what engine mods, if any, do you know were done to yours? Are you running a points ignition, or electronic?
If points, there are quite a few other tests to do to make sure it's not an ignition misfire causing your trouble under load. Or even something as simple as too large a plug gap.

Good luck.

Paul

Usually the cause of TIP-IN HESITATION on this era vehicle is a bad/mis-adjusted accelerator pump, vacuum advance and/or vacuum leak (say a lazy or stuck EGR valve/system).

A$$-um(e)-ing the engine condition is solid and in a good state of tune.

The truck is a 1878 f250 with a 351m

Any modifications to the engine that you know of? For instance, having all the "smog crap" removed? Some engines can be re-tuned for that, while some just never run right after tossing out or defeating the purpose of some of the factory equipment.
Well, they can all be re-tuned. Just depends on how much tweaking the owner is willing or able to go through to get back to the way it ran originally.

Can you post up a picture of your under-hood area so we can see what you're running? Maybe someone will be able to see a non-stock carburetor, or a missing PCV valve, or non-functioning EGR valve, or something like that.
A weak spark from a failing ignition can do it too, but that usually is accompanied by generally not running right too. Not just under acceleration.

Good luck.

Paul

Recheck your plug wires for good connections. Weak spark can result in no or poor fire in a cylinder when under load (increased fuel density).

https://cimg6.ibsrv.net/gimg/www.for...896195faa5.jpg
https://cimg2.ibsrv.net/gimg/www.for...7220915882.jpg

NEEDS MORE FUEL!!