Couple thoughts for you Lloyd. For a Grooved Q-jet, you need a spacer with the same primary bore size not just close but the same pri. bore size, and the spacer will need to be coupled to the bottom of the Q-jet so it doesnt shift around. A Groove will occupy both parent metal of the AFB AND the spacer material. Havent done this, but I think it could be done by using small dia. roll pins. Clamp the spacer to the Q-jet TB base in exact position,w/a real thin gasket between?? Drill holes thru base/spacer/gasket combo then tap in small dia. roll pins to couple all together. A 1/2 inch thick phenolic plastic or one of those brown layered looking fiber/phenolic heat insulating spacers. I'd use a drill press if I was gonna do this. Spacer needed cause there is almost no bore left under the Q-Jet primary butterfly blades. Many carb spacers I've encountered w/ individual bore holes not open center, can have different size holes than the carb barrel bore diameters.
Thing is w/ Q-jets-I've rebuilt a couple dozen. The top airhorn casting typically gets warped from heat/age and clamping force of the 2 long bolts in front. I've solved this by double gasketing and even gently sanding the bottom of the top casting. Second- Q-jets always have throttle shaft vac. leaks. I have a pro carb rebuilder where I live and he can re-bush Q-jet throttle shafts very nicely. Third- getting rods/jets to tune these, there may still be sources for those, Edelbrock made their version of Q-jets for years but have discontinued them. So a Grooved Q-jet IS possible, if you really want it...
An easier option is convert to Edelbrock Performer or Carter AFB. I've Grooved one on my Dodge 383 truck engine, Ron grooved one for a freind w/ a Ford 460 w/good results. Those are easy to Groove,common, and are very forgiving compared to Q-jets, and rebuild kits AND rods/jets are easily available thru Summit Racing and others. Q-Jet is spreadbore, Performer/AFB is "squarebore" carb. Myself I'd use an Edelbrock Performer intake man. as they will accept the AFB style carb Or the Q-Jet. For the AFB type, a thin metal plate adapter w. gaskets is used for good seal to carb base. W/ stock Chevy iron int. manifolds, they are made for the spreadbore Q-jet only, and most 4-hole adaptors to drop the AFB on the stock manifold have a weird dogleg in the pri. bores- though they will get you by.
I and others have figured out a simple way to calculate the rod/jet combo's for Performer//AFB carb's. I sent a Performer to Ron 2 yrs ago for his Ford 460 Motor Home when the Holley was giving fits w/ blown power valves etc. He Grooved the Performer and had good results.
My 3 cents Lloyd!
Tracy G
But it would be interesting to see/hear about a Grooved Q-jet!