Logo

Quadrajet rebuild or replace #17082403

Today is carb day. I am in the process of determining what direction to go here, any advice is much appreciated!

The carb that came with the running take out, Crusader 270 5.7 is a Quadrajet #17082403 with a manifold choke. Everything I've seen online is saying that fits a 454 7.4.

So my questions are:

• Was that stock for Crusader on the 350's or do you think it was a replacement by PO?

• It obviously runs, but is it the wrong application for my 350 or is it okay? I am not looking for more horse power, this is going in a 20 ft Shamrock so there will be more than enough horses to spare. In fact I would rather shoot for fuel efficiency over speed.
Are the 5.7 Merc Quadrajets the same fitment or should I be careful there, if I went with new?

• Lastly, besides Hobb's, where does everyone go for the best rebuild service for Quadrajets?

• Opinons on manifold choke vs. electric choke?

Again, thanks in advance for any advice!
Pete
 
First, whatever you do, if you have a true marine Quadrajet, don't get rid of it! There are lots of folks out there selling carbs that are converted from automotive Quadrajets. You can tell if yours is a marine carb (or at least the top part of the carb is) if it has kind of a dam around vent tube located just ahead of the primaries. Also the vent tube opening is angled.

I had my Crusader 270s' carbs rebuilt by Cliff's High Performance a couple years ago. Cliff literally wrote a book on Quadrajets and he knows the differences between automotive and marine parts and carb tuning. You can call him and ask your questions in advance if you like - he won't steer you wrong. Marine carbs seem to go to the head of the line with Cliff.

I don't have an opinion on manifold or electric chokes. My boat was converted by a previous owner to manual chokes.
 
First, whatever you do, if you have a true marine Quadrajet, don't get rid of it! There are lots of folks out there selling carbs that are converted from automotive Quadrajets. You can tell if yours is a marine carb (or at least the top part of the carb is) if it has kind of a dam around vent tube located just ahead of the primaries. Also the vent tube opening is angled.

I had my Crusader 270s' carbs rebuilt by Cliff's High Performance a couple years ago. Cliff literally wrote a book on Quadrajets and he knows the differences between automotive and marine parts and carb tuning. You can call him and ask your questions in advance if you like - he won't steer you wrong. Marine carbs seem to go to the head of the line with Cliff.

I don't have an opinion on manifold or electric chokes. My boat was converted by a previous owner to manual chokes.

Thanks DJR, I was curious at first wether or not this was in fact marine, but it does appear that it is. I am used to seeing J tubes on the Marine Holley's and other carbs, when I saw the straight vent tube I suspected it may be automotive. However, that tube opening is in fact cut on an angle and does has a "dam" around it.
I'll check out Cliff's site or give him a call. Thanks for the tips!
 
It appears that carb is off a big block...but I don't have my carb book handy...no big deal as you can always rejet it for the other engine (as needed).

I can also give a thumbs up on cliff's...I believe I introduced his name to this board many years ago...haven't heard any complaints other than sometimes he gets backed up several weeks.

you WONT find a 'new' marine quadrajet as they haven't been made in decades...Edelbrock used to make some for the auto world but I understand they quit - I suspect the profit margin just wasn't there.

The big 'tell' that it is a marine variant is the 'sight tube' fitting (typically a threaded hose barb) on the 'front' above where the fuel line connects.

On the choke, if the housing is intact, the manifold mounted coils work ok...electric coils will open faster when it is cold out...but you can adjust the linkage to get the original style to open as needed.

Finally, you can fine tune a q-jet very well...the key is taking the time to do it thoroughly. I have found they are typically calibrated on the rich side (due to OEM warranty concerns). The other thing that is damn near essential is to keep detailed notes and make one adjustment at a time...you'd be surprised at how efficient you can make it...
 
Excellent Mark, thank you. I'll tell Cliff he has fans when I call!

I agree fully with the "one adjustment at a time" practice. I think that applies to everything we do mechanically, rule it out then move to the next... if needed.
 
Cliff's did my Quadrajets a couple years ago. Absolute perfect! People ask if I have fuel injection when i fired them up.
 
So, just got off the phone with Cliff, what an awesome guy! He had so much info and was not at all bothered by my multitude of questions. In fact, I felt like I've know him for years within my first twenty seconds of speaking with him. Carb goes in a box today and will be on it's way to Ohio! He said he loves doing Marine carbs and will set mine up for the 350 as it should be. Thanks for the great recommendations gentlemen, I'll let you all know how she fires off when it's bolted down again!
 
So, just got off the phone with Cliff, what an awesome guy! He had so much info and was not at all bothered by my multitude of questions. In fact, I felt like I've know him for years within my first twenty seconds of speaking with him. Carb goes in a box today and will be on it's way to Ohio! He said he loves doing Marine carbs and will set mine up for the 350 as it should be. Thanks for the great recommendations gentlemen, I'll let you all know how she fires off when it's bolted down again!

yep, Cliff is great. My Q-jets ran perfectly for ten years with one minor rebuild in between. Depending on where you boat (I’m in the northeast), I disabled the chokes and never noticed a difference. The engine were always idling long enough while handling the lines.
 
Wondering how you made out? I have the same carb, and pretty sure it's stock on my '86 Crusader V-6, 292.

literally just installed it, hoping to get cooling system set up by the weekend and plan to test run on the stand. It took about 10 weeks at Cliffs, hope the wait was worth it. I will report after firing up.
 
Back
Top