I have a Quadra Jet that was on my Olds 350, will this work on my 454 BBC that is bone stock. Will it provide enough CFM for the 454? This is probably a elementary question...but not for a Carb challenged guy Thanx in advance for any info.
Qjets are usually 700cfm (there were some 800cfm units on Pontiacs). Chevy and GMC big block applications came with Rochester 2bbls all the time. A Rochester 2GV is plenty for all but high speed top end on a bone stock 454.
I know my 69 olds was a 500 2 barrel ....It probably would work on a big block ,But wheres the fun...............
huh, the only big block Chevy I've seen factory equipped with a 2bbl is the 1969 265 hp 396 installed in full size cars.
Sure, but that's different than saying "no way." I had a '77 C-30 with stock 2-bbl, a shop I worked for in high school had 2 366-equipped trucks with 2-bbls, and a friend's dad bought a brand new Chevelle that had one. Perhaps GM was cleaning the parts bins on the car, but the big trucks had published RPO's for that config. Of course, big trucks like their fuel at lower RPM's, so fat primaries are all they need, and the Qjet is all about the secondaries.
I still wouldnt put 500 cfm on a 454 ,,,,,Thats why I said no way,Big blocks I think need a minimum of 600 cfm
Most Quadra jets are capable of 750 CFM..some Buick and Pontiac versions were capable of around 800 CFM Ive seen them on as small a C.I.D. engines of 305 to as lage as 454's its possible they could even be used on smaller CID engines and larger than Ive seen .. they are unique in the way that they will only give the engine what it calls for due to meetering being done by vaccuum.. Granted they have to be in good condition ..if not..all bets are off
I have read that GM used 2bbls on some applications like heavy vehicles because there was a concern about having enough vacuum to operate the secondaries in some situations. 400 SBC came with a 2bbl, as did my friends big old Buick nailhead. But dispite the cfm ratings Q jets came on 4.3 V6's where in theory they would be far too big for the engine under most "street" driven applications. The key is the secondary air feed opening, I believe. That way they don't allow more than what the engine can handle. So I see no reason why one would not work on your application, if it was tuned properly. It can certainly flow more than a 2bbl.
I wish he would chime in and say its a 4 barrel ....Only reason I said about the 2 barrel I had a 69 olds factory 2 barrel carb 350 ....Of couse I put a holley on it....
Some Q-jets used on smaller motors had longer stop tabs on the secondary air door. This would keep the air door from fully opening thereby lowering the cfm.
Ive heard of people referring to them as rochester quadrajet 2 barrels.Had a parts guy that didnt know what points are ,Were in for stupid society ,Yesterday I spent 4 hours at 2 different sams clubs,I was looking for tires,They didnt have the size I wanted,Then they tell me they cant install anything bigger than what the car calls for.In this case it was a truck.Couldnt find 98 had a 99 listing ,So far that was a half hour ,I grabbed 2 tires off the shelf and left,I had a broken belt left side ....Had sears spin and balance them,I do think were in for a stupid society and sorry for the rant.....If its a 4 barrel 600 cfm is plenty ....Big blocks like smaller cfm ,Especially off the line , Street car Top end different story Driver or dragrace ,Many variables .
uh the 2 barrels are Duo-jets, says so right on top......... Duojunks if you've ever tried to fix one.
Some of the last GM Rochester two barrel carbs looked like the front half of a Quadrajet.I suppose some might not not know the difference. Lucky for me most Rochester two barrels say "2 Jet or Dual Jet",so I don't have to spend time looking into the carb to count the big holes to know it's not a four barrel..
Thanx for the input....and to clarify things for some folks Yup, the Quadra Jet I referred to IS a 4 barrel
It may have caused some confusion when the early DualJets actually had the same size carb body as the 4 bbls with the secondary air valve area cast over.
Two barrels did come standard on some large autromotive V-8's. The 1970 cuttlass 455 SX turnpike cruiser came with a two barrel carb.
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