I recently completed my truck motor wise I have been driving it on flat ground I hit m y first hill today and the truck barely made it up what could this be? I also need a new alternator if that.makes a difference 351 m with a 4 barrel intake.and.a.Holley 600 carb

If it was a steep hill I might think the floats in the carb are out of adjustment and it is either flooding or starving due to the angle. Other possibilities: timing,vacuume advance, vacuume leak, carb adjustment, etc. On flat ground how is the take off from sitting still. Does it bog down or hesitate at all? If not then I would think floats. If it does, then I would check the rest of the list. If the alternator is bad it probably doesn't have the correct voltage to properly fire the dura spark ignition or coil. As you can see there are a lot of things that can cause this with the limited info you gave and I may have missed another item or 2. I'm sure someone else will chime in but if you can give a few more details it can help narrow it down.

carb's float is off...

or its timing...

I was also thinking it was the carb it has yet to be adjusted but on flat ground the truck is fine it was just the hill it almost didnt make up... Im also pretty sure the alternator not charging the battery isnt helping either!! how would i adjust he floats on the carb?!

First you have to have adjustable floats. What's the carb PN??? Second, I tend to believe there are other symptoms if the floats are far enough out of adjustment to run fine in one scenario and not in another. Are the plugs burning lean, do you smell any excess fuel? Third, have you checked where your timing is actually at? Again, I believe there would be more symptoms if you're far enough out of time to run fine in one situation and not another. Fourth, get the alt checked...most part stores do it for free. If you're running on straight battery, more symptoms will arise. Finally, my initial thought was, what kinda gearing do you have, what size tires, how big was the hill, what speed???

Vacuum advance

The hill was pretty steep im not sure of the gearing i have 35's and also i was going about 10mph

Holley carb PART #: 0-80457SA

thtniggey said:

The hill was pretty steep im not sure of the gearing i have 35's and also i was going about 10mph

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I was thinking you were talking highway speeds. At 10mph, I dunno how to define sluggish.

thtniggey said:

Holley carb PART #: 0-80457SA

Click to expand...

Non-adjustable float per Holley's site.

It bogged down and barely made it up the hill i was doing ten at the base and by the top no longer then 100 feet you could crawl faster then the truck