Autozone carb for Duraspark swap?

[kimcrwbr1]

I have tried all sorts of different base timing adjustments and allways go to 10 degrees for best performance. My timing pointer was bent and was throwing it off I used a piston stop tool to find true TDC on the #1 piston and bent the pointer there. The idle air needles need to be turned out 3 1/2 from lightly seated and then adjusted for the highest possible vacuum pressure. The biggest mistake is to try and run the idle air too lean it also supplements the high speed circuit so putting in smaller high speed jets gives me the best top end. I`m running #42 jets and the idle air jets are out about 4 full turns each.

 

[kimcrwbr1]

If you cannot get around 17 inches mercury with a vacuum guage you need to find your vacuum leak.

 

[TenSeven]

Hi Kim, thanks.

I'm not very well versed on how carbs work but it almost seems there's a trade off going on. In that, it's either bigger jets and tighter mixture screws, or smaller jets and more open mixture screws. I'm sure it's not but, would it 'simply' be a matter of noting what size jets you already have and adjust the mixture screws to work with that size?

The second part of this is my idle vacuum, seems way too advanced. I recieved the Crane Cams Adjustable can for Fords. It's not a perfect fit and will require some adapting to my Cardone distributor if I want to use it. I've read that some guys with non-adjustable cans are simply bending the arm on it, welding a stop or using a small clamp to stop it from advancing so far.

 

[TenSeven]

Geez.......

While waiting for the #42 jets to arrive in the mail (later, I switched back to the #50's) I decided to try to finish installing and rebuilding the brakes. I had to unplug just a couple plug wires from the distributor cap to get the brake lines installed. Those two wires were #4 and #6, both feeding spark to the drivers side of the engine. Apparently, when re-installing them I inadvertently switched them, the engine would run but it caused the popping only out the drivers side exhaust. I didn't even notice because being tidy I like to line all the wires up and make it all look nice, which it did and looked totally correct, geez.

After shaking my head for awhile I switched them back, checked the others, turned the key and it started right up (without the help of a little Starter Fluid for the first time), smooth, no popping.

Still 30 DBTDC at idle with vacuum advance connected so I'll have to deal with that but it seems to be running better than ever, even since before switching the plug wires.

Now that the fear of having to replace the carb right away has subsided I'll spend some time fine tuning the metering block, main jets and timing.

 

[kimcrwbr1]

Take it back to 20 degrees with the vacuum connected to the distributor and then adjust the needles again.

 

[TenSeven]

Take it back to 20 degrees with the vacuum connected to the distributor and then adjust the needles again.

Interesting, never thought of that, I'll try it. Hopefully when revved up the mechanical advance alone will advance the timing enough.

So, if 20 DBTDC at idle with the vacuum connected, what should the timing be ideally reading at 3500rpm?

 

[kimcrwbr1]

I believe it is about 14 degrees mechanical advance so 10 base plus 10 vacuum plus 14 should be around 34-36 degrees total. Not sure what rpm the mechanical advance is all in.

 

[TenSeven]

I believe it is about 14 degrees mechanical advance so 10 base plus 10 vacuum plus 14 should be around 34-36 degrees total. Not sure what rpm the mechanical advance is all in.

Thank you Kim.