Thanks Marc.
Now that I'm out of the shop and bathed, I'll add some info:
Pic 1 Wretched 4779 core
Pic 4 I ground down a punch to fit inside of the booster entrance. There is a thinner section, hammer away and hope it breaks out cleanly. Sometimes you aren't so lucky and have to work to break the pieces out.
Following pics are me cleaning up the edges, and polishing.
Now.... really, the guys at Holley are pros, I mean the engineering staff has spent decades learning what they know. It would be foolish to think I know more than them, so I'm not changing the shape or size of the venturi, entrance, or exit. Really I'm just blueprinting and cleaning up stuff. The kind of detail that a large production company can't afford to do, but some dude in his shop is willing to spend a few hours for an extra 25cfm.
Due to this being old and in this case obviously an old racer's carb, there was damage, scratches, etc. I'm not fixing these, and so even when polished, some deep scratches will remain. I don't want to enlarge the venturi, simply blend and relax the airflow.
Further down is a picture of the tools needed to install a booster. Green loctite, a swaging tool, booster, etc.
Swage tool is critical. The one I have is from BLP (AED sells them too). I can install straight leg, downleg, and annular boosters with this one.
If you really want to clean up the main body, it's kinda hard to do with the booster in the way. You cannot reuse the boosters.
I show a comparison of the stock .140 downleg, with a .152 Stepped booster.
Testing has shown they both see the same signal, but the stepped booster flows more AND atomizes better. I use the stock .140 with 600cfm carbs as they simply don't require additional atomization due to the small size. I really like the stepped on 750cfm and larger carbs.
I've seen a leveling tool for sale after installing the boosters, you use it to make certain that it is perfectly level.
I guess that makes sense, but I do it with a snap gauge. To me it seems the distance from the minor diameter to the booster skirt is much more critical as that is where the greatest air speed and fuel draw will occur. I imagine that the skirt being further away on one side than the other that it'd pull the fuel to the closer side..... this would obviously impact distribution.
The boosters I install were perfectly centered in the venturi. You have about 5 minutes to force them around with e screwdriver before the loctite fully hardens.
I hope in the future to build a flow bench so I can test each venturi and match them all. I think this would help balance the carb greatly. (I'd also like to get a milling machine so I can stop taking everything to my neighbors).
That's about it.
Dp