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.
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!