CK5
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1974 K10 Dirty Sancho

Saved from cruel and unusual punishment
My example is my 66 C20 with the 4bbl 327 doesn't even have timed vacuum.
 
Yep. Me and @6872xtc talked about this awhile back. The port change is an emissions era thing

I don't give two shits about emissions so I should have it hooked to the straight vacuum source? Edelbrock instructions are crap btw.
 
Does it even have a vacuum advance or HEI? :D
It was points, but yes it did have vacuum advance. :p:

The disclaimer I should add is I think it may depend some on how your distributor is set up. I think there are some distributors you wouldn't want to hook up to manifold vacuum. This is part of the reason I always buy a new distributor so I know it will work with manifold vacuum.

I don't know, I used to see the debate between the 2 more in the past, but I feel like in recent years it has swung to manifold.

My other example is if you hooked up a timing light to a factory TBI truck at idle, you'd see timing at 30 degrees BTDC or better. I know the Sniper on the 454 idles way better at 30 degrees advance at idle.

Yes connect to the manifold vacuum on the right in your picture. After you've set timing without it connected.
 
I don't give two shits about emissions so I should have it hooked to the straight vacuum source? Edelbrock instructions are crap btw.
My experience is that you can hook it up either way, it just makes a difference on how you set things past that. But at the elevation that I am at, it takes some time to see which way. I used to have it hooked to manifold vacuum always, as that's how my Dad taught me. Now, I don't have anything that I can change it on..
 
It was points, but yes it did have vacuum advance. :p:

The disclaimer I should add is I think it may depend some on how your distributor is set up. I think there are some distributors you wouldn't want to hook up to manifold vacuum. This is part of the reason I always buy a new distributor so I know it will work with manifold vacuum.

I don't know, I used to see the debate between the 2 more in the past, but I feel like in recent years it has swung to manifold.

My other example is if you hooked up a timing light to a factory TBI truck at idle, you'd see timing at 30 degrees BTDC or better. I know the Sniper on the 454 idles way better at 30 degrees advance at idle.

Yes connect to the manifold vacuum on the right in your picture. After you've set timing without it connected.


the distributor is a stock GM HEI unit from a 1979 454. I bet it's retarded as hell right now.....

My experience is that you can hook it up either way, it just makes a difference on how you set things past that. But at the elevation that I am at, it takes some time to see which way. I used to have it hooked to manifold vacuum always, as that's how my Dad taught me. Now, I don't have anything that I can change it on..

I'll try it tonight, like I said earlier I've heard it both ways all over the forums and the edelbrock paperwork is not clear.
 
The latest:
Disconnected the distributor and set the timing to 11. Hook the distributor vacuum up to manifold vacuum source and it goes to 26. Rev it up and it goes to 24sh. 14 in hg of vacuum btw.

Idle air screws like to be all the way in if I’m running for high idle like edelbrock recommends

it drives way better with more timing but it’s down on power and barely has enough power to pull it up the streets around here once it hits 2nd gear.
 
Switching over to the timed vacuum source keeps the same base of 11 and jumps to 24 at 1100 rpms and stays there til the rpms drop back down.
 
Easy check is plug the hose to the vac bell, check the timing again at idle and 3k. Sounds like either the mech or vac advance is not working
 
Having the idle mixture screws turned all of the way in isn't right. That would tell me that the throttle blades could be open far enough to bypass the idle circuit some, because adjustments to them make a difference in the idle, but you should need to have them out partway for the best idle vacuum. Check that the secondary butterfly isn't cracked open slightly.

And as Bent said, you are short some timing. It looks to me that the vacuum advance is doing a good amount, but no mechanical advance, or very little. The weights can hang up, pull them off, buff them with scotch-brite, then give them a tiny bit of grease. At least you can do this for free and see what happens.
 
The idle screw situation I knew wasn’t right and that’s partially why I mentioned it. Tomorrow I’ll take a look at the throttle blades along with the distributor advance.

I should also mention that I sprayed a can of carb cleaner all over the manifold and base of the carb and didn’t notice any change in rpm.
 
It was flammable carb cleaner, right? Not sure if they sell weak stuff in California?

Martin
 
The fix is right under that can, it's been right in front of you the entire time.

I'm really no help here, I guess I can't get a jump off you anymore when I leave my refrigerator plugged in all night.

The Q-Jet still may end up on there but I need to sort out the timing and put some effort into resolving the idle mixture issue.

and the battery works btw :D
 
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