New truck with New engine problems

[Tire]

well hello again guys. I have been working on my truck( 79 blazer 350 all new holley 670 truck avenger carb, rv cam, vortec heads, holley intake. 350 turbo 203np ) geting ready to start the brand new engine since tuesday last week. So i've been spending lots of time in the garage. I got everything buttoned up and had my wife crank the engine while i watched. Well all it did was backfire through the carb repeatidly so i called my uncle he had me change the distributer 180 degress. That fixed it it fired up didnt run that great but i kept the tach @ 2000 for the first minute and a half or so, then shut it off. Tried to restart it and had numerous backfiring through the pipes and small backfires through the carb. It was still running like **** i called it a day. Today I had a guy come over the told me my wires were all backwards, he re-did them and it fired right up he used a timing light and set that also. Heres a problem i have though ( one of many ) It idles about 1000 in park and neutral, but put it in drive and the idle goes to 700-800 and sounds like it's half gonna die not to mention the truck shakes like all hell. I'm not sure if it is the old mounts i re-used or a bad or out of balance tourqe converter or what. Im good mechanically but this is my first full size chevy. Any help from you full timers would be apprciated

 

[Steve GMC]

id say adjust the carb.

 

[W7NB]

I would agree with adjusting the carb - make sure you timing is set correctly and check you vacume to make sure you don't have any leaks first, then set your idle mix screw and then idle adjustment.

If the truck smells rich while it is stumbling it could also be a float adjustment issue - just a little too high on the fuel level will cause the same problem.

Good news is, it's running! Your almost ready to play!

 

[Tire]

Well I was hoping the Holley was adjusted correctly out of the box like it said. As far as playing goes I still have to do teh suspension and a guy gave me a full hydro steer setup Im not sure if I will use yet. I do have my tires but need wheels for them ( 16.5 6 lug) to fit the 37x12.5x16.5 Goodyear MT's. For the suspension i was going for shackle filp with the two inch block that was on the truck when i got it and 6 ince springs for teh front. I went back out to the truck and started it again it sounds good idleing but just seems to struggle so much when i put it in gear.

 

[Chevy305]

Well I was hoping the Holley was adjusted correctly out of the box like it said.

I went back out to the truck and started it again it sounds good idleing but just seems to struggle so much when i put it in gear.

Nothing is ever tuned out of the box...

Sounds to me like your floats are too high. Adjust them accordingly. Since the carb is brand new it should have some nifty tuning instructions in the box if not then I can post up a link for you to get you headed on the right track.

Have you just put it in gear or have you tried to drive it? If it stumbles bogs/hesitates off idle then runs like a million $$ at after the bogging then most likely you will need a bigger accelerator pump cam.