Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Tuning suggestions for a 7044276 carb

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Shark Racer:
I'm helping a friend tune the QJet in his 68 Firebird.

The engine is a 400 with a mild cam (don't have specs, would guess duration in the 210s and LSA 110-112). Otherwise, the engine is mostly stock.


He bought the carb on ebay: http://www.ebay.com/itm/rochester-4bbl-quadrajet-7044276-1974-pontiac-400-455-date-1294-/170983509085?nma=true&si=9SQ%252BgAuBEzKXSzHwbqzQDEaS%252BBE%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

So, the info I have is this:
carb #: 7044276
Primary: 73 (looks original) jet, 48C rods
Secondary: DB
Secondary Hanger was C, IIRC

Float height: looks a little low, forgot to bring my mic with me. Should go 1/4"?

Main Air bleeds looked a little bigger than 0.070. No bushing in upper, nearly hogged out bushing in lower.

Idle air bleeds (from eyeballing) looked ~0.070 in lower, much smaller upper. Maybe in the 40s? Idle air bleed was in the air horn, behind the upper main bleed.

Is this calibration correct for the carb?

Any recommendations to start with this one? I have a good collection of jets, but no early rods. A 73/48 combo sounds like a very lean cruise to me, but what do I know? :)

I was also thinking the DB rods might be a bit lean. I have a huge quantity of CH but nothing else I'd be willing to spare.

omaha:
Id be worried about the hogged out lower air bleeds but that would be about it. Maybe a slightly fatter jet. Would be nice if you could get the apt adjuster to work. ((hard to do in those older carbs). I wouldn't worry too much about the secondary rods for now as they can be changed without taking the carb apart (very carefully of course). ...Hey aren't those 48C rods the "triple taper" rods. Did not know they used them in Pontiac carbs. Id get the main airbleeds right in line with the recipe one in the book.  Nothing looks too out of line though.

Shark Racer:
I've heard that the 48Cs are. I didn't eyeball them much when I had the carb apart.

I'm not a machinist so my visual estimates are rough at best. I'm a software engineer. :)

Cliff Ruggles:
Way too lean on the primary side.  I would install one of our kits, new jets, and metering rods.  Those carburetors used larger upper main airbleeds, and require a different calibration than other Pontiac carburetors used in that era.....Cliff

Shark Racer:
Thanks Cliff, I'll give you a call tomorrow shortly after I get up. :)

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