Holley 4175 QJet Replacement
 

Has anyone had experience replacing their tired QJets with these carbs? I am looking for better starting and equal or better performance on 350Mags. Do the fuel lines and throttle connections hook up to the same locatons as stock and is the electric choke the best way to go?

Yes, they work great,, just make sure you get on with mechanical secondaries.. The throttle linkage needs adaptors & you will need some fuel lines to make it work right.. But it is worth the upgrade.. Electric choke is nice, but many times you dont even need a choke on one. Just pump em a few times & let it idle high while it warms up..;) :)

Now, Throw out the Quadra bog or use it for an anchor.. :D

:) Jamie / Lakeside

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You know, when Merc discontinued the Q jet, they kept the spreadbore manifolds and used an adapter to bolt a Weber, aka Edelbrock, Carter on the engines.
You might want to consider a marie edelbrock 650. Similar performance and it will probably be cheaper.
You may need a new fuel line with either carb. But you can get pre-flared lines at Oreileys around here and just bend it to the correct shape.

JMO, but the carter & edelbrock are still no comparison to the holley.. The holley is easier to tune, set up & modify if you need to also the holley will out perform it.. The carter/edelbrock 's technology & purposefulness is as bad as the q jet.. There is a reason all of the non efi big boys use Holley or BG as a rule.. ;)

Jamie

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I tried Edelbrock's twice and was not happy.

Go with a Holley or a Barry Grant if you want to spend the extra $$ for an excellent carb.

:cool-smiley-027:
Agree - you won't regret the money if you size + jet 'em right.

Of course, for those who love the nostalgia of the Rochester (aka all I could afford this year)...here's a before and after.

:cool-smiley-027:

Ok, Ok these are in the garage...:cool-smiley-011:

On a stock 350 mag I doubt anyone would notice the performance difference to be worth the $100 difference in price.
On my 68 vette, high compression, big cam I would agree. I'm running a holley on that and used to run holleys on my supercharged boat motors.
But my cruiser is running 40 year old Carters. It starts better and runs smoother than most of my friends efi motors. Oh yeah, and I dont have to worry about accelerator pump diaphram failures causing a gas leak right under my a$$.
My $0.02

http://www.holley.com/0-80552.asp

This is the carb. It is only available with vac secondaries and spread bore design, which is fine with me. I am looking for a bolt-on swap that doesn't require changing fuel lines, throttle setup and the height of the flame arrestors. I am trying to keep it simple, if this carb can't do it, I'll look at something else.

Nice bolt - on
 

:cool-smiley-027:I replaced the QJet I had on the boat for 20 years with an Edelbrock last year, and the difference is remarkable - easier starting, smoother and stronger acceleration, but about the same WOT.

The Holley is a much nicer piece and should serve you well.