[mtncat]

Ok, for all the edelbrock fans out there. This is a model 1405. It was on a chevy 305 stock motor. Had lot's of trouble getting it tuned in on that motor as I run elevations from around 3000ft to 8000ft daily. Finally got it running good with .095 jets in the front, .089 in the rear and .073X.052 metering rods.
Now it's on a new 350, edelbrock performer intake, headers and dual exhaust and runs like &**&)*)(
Edelbrock has not been able to get it right. They have made several sugestions, some of which improved it a bit and some that were in the toilet.
Currently they have me trying .098 front, .095 rear and the .073X.052 rods.
And playing with the step up springs.
Currently when I'm at the lower elevations it runs pretty rough, low RPM, cruising speeds under 45mph it keeps "cutting out" when I run the RPM's up it runs a little better. Pulling the hill and higher elevations it does the same thing unless I down shift and run the RPM's up again. In the mornings on start up and running the RPM's up a bit it is doing a little light back firing.
Any thoughts and suggestons are REALLY appreciated.
The timing is on and the idle mixture screws are set according to specs.
Thanks

[flipp121]

My exerience with edelbrock carbs has been very ****ty as well. So ****ty in fact that there is a $300 1406 sitting in my basement and a 40 year old rochester 2-barrel currently sitting on my car. Its been my lesson that unless you have a dyno or some sort of oxygen sensor or some natural talent for carbs to leave them the hell alone the stock carb works perfectly well. That aside, when i was running the 1406 back and forth between calgary and edmonton on the weekends, there is about a 1200ft difference in elevation between the two cities, id tune the idle mixture in edmonton and the car would be stinking of gas and running like a dog by the time i hit calgary. Its my impression that carbs dont run very well when theres a huge altitude change like that and require constant tuning... anyone else? Oh and also my rochester is a million times less picky about how the idle mixture is set compared to that POS edelbrock carburetor...what I would do if i was in your shoes is get a qjet, or better yet find the qjet that came with the 350 originally and work with that my 2cents,
Mark
Oh and just like you i spend hours on the phone with edelbrock as they told me to buy these springs buy these acelerator pump nozzles, these rods, how about a fuel pressure regulator? holy GOD, by the time i was through i was out about $200 in 'edelbrock' accessories...thats good buisness, they never did get it right and although i appreciate the time the spent on the phone with me it didnt help and seemed sure enough they were just trying to sell me their stuff. Slapped on the old 2barrel with a $30 carb kit rebuilt at home in 2 hours and it just ran like a dream. No fuel pressure regulators, no this no that....I also didnt buy an oversize carb cause the guys at the speed shop recommended the 600cfm, but the first time on the phone i got a guy who told me i should go and buy the smaller 500cfm...wow never again, lesson learned...

[Ironmahn]

If you still have the parts, and you haven't done this already. I'd start at the baseline for this model of:
Main Jet Primary .100"
Main Jet Secondary .095"
Metering Rod (Primary Only) .070" x .047"
Step-Up Spring orange (5")
Needle & Seat .0935"
Float Height 7/16"