I have a 351W with a holley intake and a holley 4bbl 750cfm with a manual choke. It runs but it kinda stutters/misses while it idles and when you get "on it" it kinda dies out at first then goes...I put a new pcv?? pvc?? valve in and I attached it to the outlet at the back of the carb and it runs alittle stronger but still with the same issue... Thoughts??? conclusions??

I am a lil green so... by me dinner before tearin me a new one!!!!!!

 

Sounds to me like to much gas. Make sure your carb is adjusted and jetted for your alt. My car did the same thing and I had to jet it down as I live at 7k feet. You might talk to Holly tech support too.
Walt

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Just needs a tune up.

 

Thanks I think that too, I live in orlando FL and I dont think it needs a tune up it is a brand new engine, just rebuilt with all new parts..I think it might be a vacuum issues, there is two ports on the distirbutor and it runs alot better if I switch it to the top side port instead of the valve that goes to the front but it feels like I lost a little of my bottom end torque..are both valves supposed to be hooked up to somehting on the engine?

 

Is it a new carb or one you got from someone used? is it mechanical secondary or vacuum? A vacuum one will have a large roundish device on the passenger side that is connected to the secondary throttle arm. A mechanical one will have two accelerator pumps and will shoot gasoline into all four barrels when you mash the gas pedal. What camshaft and gears does it have? Automatic or manual trans? Stall converter if auto? Which intake is it, single plane or dual plane?


if you floor it, and it seems to die and stop running, then takes off, well welcome to the world of BOG. If it just has a slight hesitation that isnt a bog, and is usually the float level being too low or not enough squirter shot from the accel pumps. lean can cause a bog so can rich. Lean is more prevalent because there isnt enough fuel available when the throttle blades open. it takes a bit of time to siphon fuel from the bowls, that is why there is an accel pump, it fills in the gap so to speak.

Cant really tell you what to change without more info, driving it would be nice but I doubt you live in Upper Michigan.. A carb number from the choke horn would help considerably.. 4150 or 4160, or something else, just need that to figure out what is goin on.

 

its a 4150 with a manual choke, secondary vacuum. no stall converter but I do have a C4 trans with something in it that makes it a C5 , an overdrive type gear centrifuge something..Its 3 am...sue me... and that is not shifting right either.. I ahve to give it a lot of gas before it goes in any gear..but everything is stock except the intake and the carb which is the holley 4bbl 750 cfm. I had the points taken out and put in a pertronix set up..