Carb adapter good idea?

[J-20DartGuy]

Hi guys, great site. Learned a lot from you guys and one day I may get to come up with an answer for someone. Right now I'm looking for one myself. I have a 77 360 in an 81 J-20,40-50k on a rebuild for propane changed back to gas. Has a 4bbl manifold from a 401 and I've adapted an Edelbrock 1405 manual choke to it using one of those aluminum tapered down plates about an inch thick. The problem I seem to be having is that the carb runs rich. I can't lean it out enough to have clean exhaust tips. The exhaust smells rich, not a clean smell. Could these adapter plate things be the trouble? When you look down the carb throat its not really a straight shot through. Would this not allow enough air in? Any ideas? The carb is only 3 years old with maybe 15k on it. The butterfly is coming right to the stop when the choke is off. Appreciate any replys. Andy.

[Bandit]

I've got a 2bbl intake if your interested. Not sure how much it would cost to ship though? (I'm in Kentucky) Not even sure that would fix your problem? If it used to run on propane it might have timing issues.

[Ralph]

You more likely need to change the metering rods. That's a pretty good carb you've got, and it's simple enough that nothing should wear out in just 3 years' usage. (Although they do seem to have a high frequency of bad accelerator pumps, which would cause a bogging problem when taking off from a standstill.)

So I think you simply need to set up the carb for the environment in which it runs. Edelbrock's website has a good technical advice page.

[Joe J-Truck]

Edelbrock makes a great carb, but like any aftermarket carb, you need to tune it for your particular application. I'd try and tune your idle mixture first before you go swapping metering rods. The main metering system is not used at idle. Hook a vacuum tester to a intake manifold vacuum source, then, with the engine running, turn in your idle mixture screws all the way in. (not hard, you don't want to damage the needles against their seats) then 1/4 of a turn out either side until your engine is pulling the highest possible idle vacuum. Then reset your timing using an inductive style timing light to factory spec. You may have to adjust timing as you set the idle mixture. Make sure your plugs are good and clean (they're probably all sooty and gross! you may need new ones) and all other ignition system components are functioning without a problem before you go tuning.
Hope this helps.

[Veepster]

you did not tell us when it is running rich...idle only? cruising? acceleration?..........are you having drivability problems?......

[J-20DartGuy]

In answer to Veepster; drivability is good with no bogging. I think it runs rich right through the revs cuz the tail pipes never clear up, though the ehaust is not noticably black. I'll try to play with the idle mixture screws with a vaccuum guage along with setting the timing while doing so. I didn't think the timing would go out while setting the idle mix. I'll post back and let you know what happens. If this dont work how do I know hat metering rods to get? Thanks again for your replies. Andy