1972 Thermoquad (340) Main Jet Well Inspection Question?

Get you a tube of this.
https://www.amazon.com/Seal-All-380113-Adhesive-2-Ounce/dp/B0015AE0AU?tag=fabo03-20
It works GOOD. It's runny, so get you a little brush and brush a coat or three on the seam where the main jet wells are glued on. It's also impervious to gasoline, which JB Weld is NOT. So it will last. No need to remove the main jet wells. Just clean them up good with isopropol alcohol, let that dry good and apply the Seal All.