Just finished rebuild on my 76. 9to1 pistons. stock 882 heads ported
mallory distributor, edelbock rpm intake, cam with .447valve lift and 222
duration at .050 vacume 11" at idle
carb all orignal with new kit 77 mainjet 48 rod secondary rod ch
fuel pressure is 6 psi to rich a idle to lean at wot. any suggestion before I start buying parts which power spring, jet combo and mods.

Any advice would be nice.

 

Project -
How is your timing set up?

 

Got some questions project76
How do you know it is to lean at WOT ? do you have a dyno printout that maybe you can post here for us to see.

How is the air cleaner setup ? stock ?

 

Project -
Not knowing exactly how you're set up, here are a few thoughts:

First, your current jetting setup, if all other issues are correct with your carb (correct type float, correct float level, etc.) should not produce a rich idle or lean WOT condition. 77 main jets are the biggest you want to go with for your application, and the CH rods are very good universal rods for a performance motor. The setup should work very well if everything else is on the money.

The first thing I would do is do a good setup on your timing. You cannot tune a carb to compensate for incorrect ignition curve, and your symptoms are indicative of incorrect timing.

With your setup, you need to be running 18 degrees initial advance with 36 degrees total. Achieving this may require that you install an advance stop bushing in the distributor to shorten the advance curve slightly, limiting the mechanical advance to about 18 degrees. Install a soft set of springs allowing this curve to slam in fully and quickly by 2500 rpm. Use a vacuum advance control unit with no more than 16 degrees of advance. This setup will give you a very good idle with outstanding WOT performance. But it's critical that you get at least 18 degres initial timing at idle and 36 total. Don't try tuning the carb until you hit this spec.

Once this is done, verify that your power piston is not jammed in the bore, and set the down-stop limit screw so that .020" of the brass sleeve extends above the lip on the plastic piston retainer. Power piston seated height has a big effect on idle and cruise mixture control.

Set idle mixture screws to 4 turns out from lightly seated.

With this combination of power piston height and idle mixture screws, you should have plenty of adjustment to run the idle mixture either rich or lean - there should be no issue with rich mixture on your existing jet combo. With the power piston down-stop adjustment plug removed out of the airhorn (punch this out when you have the airhorn removed for initial piston setup), you can visually observe if the piston is pulled all the way down during engine idle operation. If the piston is down while the engine is running, you do not need to change the power piston spring. If, for any reason, the piston s not seated at idle, install a softer spring.

WOT mixture, with the 77 Jets, can only be richened up with a secondary rod change. You might want to make sure you really are lean at WOT, as I've never seen a lean setup wth a 77 main/CH secondary combination. The CH rods are .057" in diameter; if you need to richen this, you can go with a set of DA rods that measure .044". Part number is 7046010.

Good luck with the tuning!

 

you give me a lot to look at . took carb apart will soak over night
just to make sure nothing is pluged up on secondarys.
when I rebuild it I did set the power piston a little higher
thinking it will be a bit richer.
as for my timing I think you are right I set it a 11 degrees
when I first got it running and havent looked sence.
one last question should I drill out the idle discharge ports
with only 11" of vacume