having problems keep it running

[Buddy]

I am building an 85 4x4 gmc. It has a 305 with an eldbrock dome and a 600 holly carb on it. My problem is that the truck starts somewhat good but doesn't ever seem to stay running at idle. I always have to play with throtle to keep it going. I see people saying that it could be the timing, not sure how to do that yet. Next thing I hear people saying is that it could be the vacum advance. I cant seem to find the vacum adavnce on my truck. dont know if that because everything is aftermarket or what. Any advice would be great!

[jaredts]

Does it idle poorly when its cold or all the time regardless of temp.?

[Buddy]

i am not running thos truck as of yet, still in the build process. so it is just when i start it and try to run it in the shop

[jaredts]

There's at least a hundred things it could be!  Need to know what you've done so far and what kind of carburetor/condition of carburetor.  Once everything is right (choke adjustment, timing, no vacuum leaks) the idle speed screw should be run up to a proper idle speed.  If you haven't yet, you might let the engine get to temp. and see how it idles.