i just put a new Edlebrock aluminum egr manifold on my 400m and a new street avenger carb on it. hooked everything up, made sure the electric choke worked good, set the timing and started it and let it run for a little bit. it seems to studder alot, i rev the engine and there is like a pause then it revs up. i put it into drive and it starts to want to die and when i give it gas it wants to die even more, but went i start down the road its fine. pull up to a stop sign and it wants to die again, ther i have to put it into neutral to stop from killing it. oh i also put a new blaster 2 coil on it if that helps solve the problem. im open to any suggestions. im leaning more towards the vacuum leak and if so how do i find it.

 

If the hoses are old...replace them

One way to find vacuum leaks is to use some carb cleaner spray.
With the straw nozzle point and spary at every vacuum connection.

Along the seam of where the intake meets the head.

If the engine changes its running condition,there's your leak

 

Sure your float level is right? Vacuum gauges are cheap. Tells you a lot about an engine, but not many people use 'em anymore.

 

i figured it out. my power valve blew. i read somewhere that when your engine backfires that it will usually blow the power valve on holley's. i just need to get a new on. thanks guys. by the way i did test for vacuume leaks and everything turned up ok, no leaks.

 

Newer Holley carbs have a check valve that is "supposed" to stop that. There is a retrofit kit for that also for the older carbs. The power valve is a major weakness on Holley and Motorcraft carbs. Then you add the leaky gaskets... Now you know why I use Edelbrock!

 

yeah and i just bought this street avenger a couple months ago too, and i also use an edelbrock on my other truck no problems with that. haha thanks