Hello all i am new to these forums because i recently picked up a 1986 Iroc Z it has a 70's 4bolt 350 carb engine.My problem is when its idling the the car has a sporadic miss and cant hold its rpms it bounces from 700 to 1000 rpm (never dying or stalling),The car is also running Super rich, eye burning in fact .There is also some stuttering at higher rpms no back fire feels like loss of spark.

Things i have tried : Adjusting carb,spark plugs wires one was burnt to my header but it did not fix the problem,new pcv,air filter,fuel filter,e3 plugs with no luck.

One thing i wonder about is the intake is a quad so it has a quad to 4 barrel adapter with a 1" spacer on top of that not sure if this may cause a problem?I checked the gaskets for leaks and they were fine.

The engine has a edlebrock intake,(NEW) edlebrock 600 cfm electronic choke,Hooker Headers,700r4 no electronics or smog,New wires,new e3 plugs.

Any ideas would be appreciated.I will make a video and put it on youtube maybe it will help narrow down the problem.

 

You didn't mention checking the timing. More advance is more lean. Make sure you have 6-12 degrees initial advance, with the vacuum advance blocked off, and make sure your centrifugal advance is at least doing something. Try that.

 

… wrong thread

 

Ok multi tip plugs are for center plug chamber type cylinder heads, otherwise your just hurting flame travel. Use standard plugs! I'd use regular copper plugs until you figure the tune out cause once fouled your better of replacing.

You prob have a vac leak somewhere, carb, vac line, intake, bad valves idk

Ditch the spacer but keep adapter plate if you need it, well if it's the thin one like this https://www.summitracing.com/parts/edl-2732

I don't know how to tune an eddy carb so I suggest you check youtube and old threads for as much info as you can find.

A MSD box would help mask your problem because it will fire fouled plugs at lower rpm, lots of track guys use em and don't bother to tune for street.

Hope you got that trans figured out for lock-up or your gonna burn it up, I'll let others suggest ways to handle that.

Alum intakes are poor grounds cause alum corrodes really fast, MSD says they are the cause for a lot of HEI problems and why their version of an HEI has a dedicated ground wire.

Always a good idea to find and clean/replace all grounds in an older vehicle, head lights get brighter and things work better.

 

Always best to check the date of the post your responding to , this thread is a mistaken bump of a 10 year old question by the original poster .....

 

LOL happens, someone bumped one of my old threads on another forum just recently and I was the one who corrected the replyer.

 

Sorry it was my bad, went to reply to a thread and accidentally scrolled town to far into this thread. Wish there was a way to delete a comment.