Would you use a 800 qudrajet Marine carb on a first gen?

[kingofhill21]

I was curious what you all think of this carb its a marine. Now what is your opinion i want the truth.

[CHEV 383]

Sorry, I do not have the knowledge to help. If it were free, I might give it a try if no one has a serious objection or if it will hurt the car. I am running a Barry Grant 750 mechanical.

Nice looking Bird!!!!!

[81DaytonaPaceCar]

I was curious what you all think of this carb its a marine. Now what is your opinion i want the truth.

Yep...every day...should work very well for you...just double check and make sure it mates to your intake and air cleaner assembly correctly...

[TSTONE]

im thinking it might need to be rejetted though?

[81DaytonaPaceCar]

im thinking it might need to be rejetted though?

Maybe...but I would think that a marine version would have larger jets to begin with...could be an ideal solution for a slightly lumpy 455...

Throw 'er on there and see how she runs...

[TSTONE]

you can always try it - my thought was most marine carbs are jetted for running at WOT the majority of the time - id be concerned about dumping to much fuel and washing a piston

[81DaytonaPaceCar]

you can always try it - my thought was most marine carbs are jetted for running at WOT the majority of the time - id be concerned about dumping to much fuel and washing a piston

Yep...agreed...the secondaries should be huge...but I'd wager the primaries are a stock size...even marine motors have to idle around in a reasonable fashion...kinda depends on what it came off of...

That said, I wouldn't be afraid of even running a 950 CFM on a warmed over 455...if you really wanted to be safe, you could just lean out the secondaries at start up, drive it for a while and dial it in...

As a side note, while you're doing this, double check the throttle cable and linkage and make sure that it has enough travel to open the secondaries fully...often when swapping carbs, the throttle linkage is in a different fore-aft location and causing unwanted slop in the cable...

[TSTONE]

makes sense as long as you lean the secondaries

[kingofhill21]

Yep...agreed...the secondaries should be huge...but I'd wager the primaries are a stock size...even marine motors have to idle around in a reasonable fashion...kinda depends on what it came off of...

That said, I wouldn't be afraid of even running a 950 CFM on a warmed over 455...if you really wanted to be safe, you could just lean out the secondaries at start up, drive it for a while and dial it in...

As a side note, while you're doing this, double check the throttle cable and linkage and make sure that it has enough travel to open the secondaries fully...often when swapping carbs, the throttle linkage is in a different fore-aft location and causing unwanted slop in the cable...

Well that guy that is going to sell it to me has been deal with carbs for a long time. He rebuilt the carb himself for an auto application. I am sure he put in the right size jets and what not.

[kammi10]

the problem being with the jets is every motor is different so there is no telling what jets he has in it until you look so you don;t know if they are right or not

[kingofhill21]

the problem being with the jets is every motor is different so there is no telling what jets he has in it until you look so you don;t know if they are right or not

Yeah he is helping me install it and tune it and has other jets for it too!

[TSTONE]

then you should be fine

[81DaytonaPaceCar]

then you should be fine

Yep...you're golden...

[TB2]

Quadrajets are great carbs. I have run many of them over the years. The small primaries should help you out with gas milage cruising around town. The only problem with them is they are alot more difficult to adjust than a Holley as far as float adjustments, changing jets, etc. And almost nobody stocks jets and performance parts for them. I wouldn't hesitate running a properly tuned one though.

[81DaytonaPaceCar]

Quadrajet carbs may be one of the most misunderstood components in automotive history.

They were developed with a near unlimited budget by GM in the late 50s to mid 60s, and contain roughly half the components of a comparable Holley or Barry Grant (Demon) carb. Where Holleys and BGs do their work through mechanical linkages and actuations, Quads were developed with very extensive (years of it) airflow development through minimal numbers of moving parts, just simple design of the airflow chambers themselves to create better atomazation during real world street driving through (moderate) high performance applications.

Yes, there really is a reason why that little butterfly is cocked at the angle it's at...no, don't try to stand it up straight...no, don't try to lay it flat...that little angle really is important...

The center mounted bowl design is optimally located for all moderately inspired performace applications.

The small primaries were optimal for gas mileage and throttle response.

Properly tuned, you can make the argument they are the best factory carbs ever issued.

As they were developed to be the "best" possible factory performing carb, they do have some performance shortcomings.

"Back in the day", the design of Quads was very misunderstood. Can you make a high performance Quad?

Yes...but their early reputation in the hot rodding world was so poor, nobody bothered to do anything about it for years (i.e. the design was so simplistically complicated that the backyard hot rodder didn't have the knowledge to HOW to make 'em work...thus they were written off as "Quadrajunks")

I don't think they ever made a Quad larger than 800 CFM...could be wrong. So if you're pumping 800 hp, you're almost forced to go another route, unless you run dual quads.

The second biggest shortcoming (especially "back in the day") was the bowl design is prone to leakage...very common...although there are kits to fix this now days.

The biggest shortcoming was that GM just slapped the same carb on a variety of motors with little regard to performance for the individual vehicle. Thus they developed a global knock for being responsive in one vehicle, while having a serious problem in another.

But all in all, a great carb...especially tuned by somebody that knows them...maybe the best ever...