Having some fueling issues on my car (ITS TR8, 175 CD Zenith-Stromberg carbutretors). It's rich at idle, VERY lean through the power band (confirmed at a dyno day).

I've got the "rich" needles, but stock jets. Grose jets are now available for this carburetor for the first time in a while. By looking at the design, it appears to replace the entire needle assembly? There is a ball that sits in the needle seat and I assume it is used to regulate fuel flow, as opposed to the needle? Anyone have any experience with these? Are they an acceptable alternative to a finding new, larger diameter standard jets?

Thanks.