real time help- vaccum lines

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Joined
May 24, 2006
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so im out here working on my truck... just fired it up after new motor was put in. And the carb is back firing on me. the only way i can get it to not back fire is setting the timing so the idle is at like 1000 rpm. so i was wondering if i have my vaccum lines right? i cant really think of anything else. here are some pics of it set up

the manifold line goes to the dist
the carb plate line goes to the side plate
and the rest you can see on the pics

its a weber 38mm on Fmotor.

if this isnt right what should it be... and if they are right how can i fix this problem?
IMG_0455.webp
IMG_0454.webp
IMG_0453.webp
 
The stock 69-75 dissy should not be connected to vacuum. It is a vac retard dissy (bad thing).

If the dissy has been switched to a vac advance type, then it should be connected to a ported vac fitting on the carb.

Once it's hooked up right, set the base timing to what you want it to be (10* BTDC is a good start), then adjust the idle speed screw on the carb.
 
just fired it up after new motor was put in. And the carb is back firing on me.

Check the valve adjustment......

Needs to be done a couple of times after a run-in period..........
 

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