I bought a lil red express with a 360, that the previous owner had "modified" and I am trying to even it out a very rough idle. The last owner put in a purple shaft 284lift/484dur, a Wieand Stealth intake, Edelbrock 750 (which I just replaced with an electric choke 600), long tube headers ,and a set of used J heads.

Now the only way I can start the truck is if the timing is set advanced to 34-36 at idle with a total advance of 44. The idle is very "loopie" and it is hard to start when hot. If the truck is running I can bring the timming back down to 19-20 at idle but no lower and it will run fine at that, however I can not restart it there. I have to bring it back to 34-36 advanced.

Sounds like something is not aligned right (cam, timing chain, ???) when he reassembled the motor. I am not a motor builder but would like to know what I would be getting into to have this fixed.

Any advice?

 

If you don't have one, you need a distributor that will lock in the total advance. Lock it in at 35 degrees total advance at 2000 rpm with the vacuum advance plugged.. Then you can reconnect and set the vacuum advance.

 

You got the lift and duration swapped in your info. But we get it
Sounds like you sound be on the rite track. Maybe the cam is installed wrong, like off a tooth or 180* out? Check the Vacuum reading. I bet its way low, and if you have power disc brake. the brake are probably kind of lame and dont work too well?
I think the car is too small for that cam. Try the other carb back on it and see if its better?
Also, If its the low compression engine? Its a tough tune !!!!
Just an FYI. I had to pull that cam and still have it on the shelf.

 

It certainly is! An absolute must is to enlarge the idle syphon tubes of any carburetor you may choose to at least 0.043 to get enough idle fuel for idle mixture adjustment. And that takes a bit of skill and some drilling (and tapping and plugging "Holley").

 

True. I try not to get to lost. Or Get people lost when I make suggestions...lol I just kind of like to point them in the rite direction, simply because Im not their to work on it.
But tuning some of this stuff that was so lean to begin with even back when we had leaded fuel has become a pure nightmare in it's self. You almost have to tune it as if your tuning something that is running them on Alcohol...lol

 

And he'll need at least a 10" converter to make it street comfortable, even if he can do the advanced carburetor work. Or ditch the cam.

 

Ok, I said I was not a builder as evidence of this post.
ALL is good. I did not know I was supposed to plug the vacuum advance on the disti when I time the motor. Once I did that it is right at 16deg. Also is was VERY lean. I pulled the plugs and they were white... I enriched the idle mixture and now the thing is running much better and I am not worried about burning a valve. Also The tourqueflite throttle position linkage was not hooked up. I got it back in order and now it shifts great and kicksdown.
It is a much happier truck.. Thanks for the advice and putting up with a newbie.

 

Or at least something with some stall in it...

 

Thanks for the great subject,,,, Hope you don't think we where bagging on you... That is not the case at all... We just throw things out and hope something gets you back up and running so that you are happy.
Glad you got it running better... Lets keep making you and it better...

 

All good. I appreciate all of your ideas. I will post if I have more issues.

 

When I ran that cam it liked 20 initial and 14 centrifugal.

 

That's right where I settled on. Any lower and I have hard starts, higher I lose my lowend torque. Thank you very much.

I also figured out I had a low fuel pressure and a percolating issue. The fan clutch was wasted. New fan clutch, thermal isolator between carb and intake, thermal sleeve over fuel lines and a new fuel pump. The truck is now running and starting great.

 

Making Great progress !!!! AWESOME

 

More progress. Maybe these things will help the next guy. So I was still having a rough idle and hard hot starts so I started going through the ignition system. Adjusted the air gap on the magnetic pick up, swapped out the disticap and rotor (the coil button was almost melted away from a weak rotor spring), new ignition control module, new ballast. The Coil is good, I ran a replacement and felt a drop off in power so back on went the hot yellow one. I reset the timing to 18/34. It ran like a scalded cat, but would not restart until I put it back at 21/36 (I lost some lowend torque but at least I can start it again). Then last night I rebuilt the Edelbrock 750 that came on the truck. If you remember I went to a Edelbrock 600 and things got stable, but I thought "I have this 750 here that is like new, I will do a complete teardown, clean, replace the gaskets and rebuild it." So I warmed up the truck on the 600 and took it out for a test drive this morning, then put on the 750 and WHOA!, it is way faster on the 750. It is idling much smoother and has plenty of torque. I can spin the tires through first and halfway through second.... I thought 750 was too much for this 360, but the seat of the pants don't lie.

 

Glad you have found your problem... Mopar on !!!