The Dodge Challenger Message Board

Hello everybody,i found this forum very interesting and i hope someone has some helpul tips for me.Challenger has a 440 bored 0.60 w KB pistons. Old but ported stage4 heads and a Weiand dual plane intake.Cam is Hughes 2330 Int504/Exh515 Dur at 0,50 223/230 ,hydraulic lifters,stock exhaust manifolds.Carb is Edelbrock AVS800 with stock dual snorkel and KN filter element.Mopar electronic ignition upgraded with weights advance lighter spring inside.Despite to almost factory look under hood the engine when running unveal some healty power.The big problem is it really smells bad of unburned fuel although it doesn't smoke at all.I tried to lean idle mixture screws as much as possible and to chance initial advance from very advanced to quite retarded but didn't get it running crisper and cleaner. i don't want to steal you more time,any help would be appreciated. thanks Roberto

You have a bigger than stock duration camshaft.

For it to run good you need to make some changes to suit that.

First of all you need at least 14 degrees advance at idle. In fact advance it until it will not start easily or "kicks back" and then back off the timing two degrees.

Set mechanical advance at a max of 34 degrees at 3000rpm. You might need to modify the distributor advance curve to take some degrees out.

Probably not a good idea to run with a vacuum advance at all.

This change will help burn the fuel in the cylinders better.

Now set your idle speed to 800 - 850rpm.

Put a vacuum gauge on the port that fed vacuum to the distributor advance. At idle there should be no vacuum at all on this port.

If there is you need to set the secondary throttle blades open slightly (just a crack to let in a little air) so that you can close the primary throttle blades more to loose the vacuum.
Another way is to drill two small holes in the primary throttle blades.

I am not sure if there is any provisions for allowing more air in on that particular carb.

Once you have the correct idle speed and no vacuum on the distributor port you need to block this port off with a rubber plug and put your vacuum gauge onto manifold vacuum now.

Adjust the idle mixture screws until you just get max manifold vacuum. Then back off lean a quarter of a turn. Make sure both idle mixture screws are turned out the same number of turns.

Now note what your idle manifold vacuum is and fit the correct rated metering rod springs for that reading. Instructions on how to do this usually come with the carb.

Once you have done this things should be MUCH better. Any rich or lean condition after that is down to carb tuning on the metering rods and jets.

Thank You Dave!
I appreciated your very technical tip for my car, I'll need some time in order to make all tests you indicated and check back issues of Mopar magazines to perform some of necessary steps...anyway I'll you know if I solve the problem.
Roberto
PS. I had a quick view at your website, it's a great job well done,thanks