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sb 350 timing/fuel issue

1K views 8 replies 5 participants last post by  dahoyle 
#1 ·
I'm having a horrible time getting the correct timing/fuel mixture for my 76 Sb 350. I have an RV cam, Quadrajet w/750 CFM and low rise intake. It seems no matter where I set my timing the engine/exhaust smells like fuel. There is no leak in the carb though, so I know it's burning way to rich.

I have the idle adjustment screws set at 2.5 turns out and the engine idles at 850-900 RPMs. RIght now my plugs are pretty black and that is just from playing around trying to get the timing right, maybe one trip in the woods.

I mentioned my problem at autozone when buying my new set of plugs, and they helped me get a cooler/hotter (which ever one was what I needed) plug to try out.

I'm just frustrated with the tuning. I don't konw if 750CFM is to much combined with the low rise intake which does'nt allow for much air/fuel seperation? And from that, no matter what I do with tuning it is just going to run rich?

I tried to set the timing at 10-12 but it just (for lack of a better word) chokes...The engine sounds best at (guessing) 20 deg advanced. I'm guessing because that is obviously way off the timing bar on the HB.

Sounds like a mess, any suggestions?
 
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#2 ·
It's been a long time since I've messed with a non-injected smallblock, but way back when: I'd set timing at top end. If your distributor has vacuum advance, leave that hooked up, and set timing at about 36-38 degrees at full advance.......so, at 2000-2200 rpm you should have 36-38 degrees. You have to have a "degree tape" on your harmonic balancer to do this though.
you ask about air/fuel ratio.....do you have a vacuum gauge?
 
#6 · (Edited)
Sounds to me like you are just fucked. You have a fuel issue, and you are trying to fix it by switching plugs, and adjusting timing. That tells me that you probably don't have a snowballs chance of getting it right. That, and you apparently thing that air/fuel separation is a good thing. I'm guessing that most of this is pretty much over your head, and you are totally clueless.

I'll give you the benefit of the doubt, and make the assumption that you just had a brain fart and are all better now, and ready to find the real problem.

Here's a clue...... it's a fucking fuel issue. That means pump/carb. Since it is fouling plugs at idle, I'm going to guess that you "might have a choke/linkage issue. That's the first place I would look, anyways. I'd also verify the fuel pressure, replace the needle and seat. Hell, overhaul the damn thing. Since you are stating that it is a 750CFM quadrajet, I'm going to guess that it's an aftermarket, most likely Edelbrock. Have you considered downloading the tuning guide.

Quadrajets are one of the best carburetors in the world, with the right guy tuning them. They can be tuned in almost as precisely as some of the FI systems. With the wrong guy, they are a total fucking nightmare. You are probably the wrong person for the job.
 
#8 ·
What is your problem? You try to come off as knowing everything. But if you seriously think the way you type, you are anything but intelligent. You really just seem like a jerk, I'm sorry for you sir.

To everyone else who took the time to read my post and try to help a guy out, thank you!
 
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