I'm curious if anyone else who has an Edelbrock 1403 (500 CFM) carburetor could share what jet and rod combination worked for them on their 300. I have been running this carburetor with an Offy DP intake for a little over 4 years now. I ran it for some time with the stock calibration and it was quite rich (poor gas mileage, rich-smelling exhaust). I have the tackle box full of different rods, jets and springs. After some time I changed the rods out to the next lean stage (swap factory 1460 rod for 1461 rod). It's better, but not as efficient as I think it could be.

I'm about to open up the carburetor for a rebuild and thought about going the next step lean on the jets too. I'm following the chart in the manual. I'm curious if anyone has a particular combination that worked for them. I did find that leaning out the accelerator pump to the lowest setting helped quite a bit. Before I did that, the truck would throw soot out the exhaust. But now I'd like to fine tune the carburetor even more.

Thanks guys!

 

I've got the same carb on an Offy C. It's been too long since I opened it up, can't remember the rod/jet combo. IIRC I actually had to go a step richer in the power mode and switched to a stiffer set of springs. And use the biggest pump shot with bigger pump nozzles. It still runs a bit lean right off idle.

I've also got a wideband O2 sensor that helps a lot with tuning. With a vacuum gauge and that you can see exactly what the carb is doing. I'm happy to let you borrow it if you like, shoot me a pm.

 

Thanks for the offer on the vacuum gauge, I do have one and rely upon it heavily.

I'm surprised to hear that you had to richen yours; mine ran pretty rich out of the box (it's a lot of carburetor for that motor). Thanks for the feedback though.

Any other thoughts?

 

I meant you could borrow the O2 sensor if you'd like. My EFI exhaust manifolds have O2 sensor bungs machined in so it's easy peasy to hook up.