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383 carb questions

C

corncrackerjimmy

New member
I have a 91 Ambassador and am planning on building a 383 stroker for it. Im building it out of a mercruiser black scorpion engine, so roller cam and vortec heads. I am getting mixed information on what carb to run. My machine shop in town says no way to running my quadrajet on there. I talked to Dennis Moore in california and he says the quad would be fine. Any suggestions would be great. Thanks
 
You can jet up the quad. I ran a quad on my 71 455H.O. Judge and she flat out ripped. The small primary's give you extreme low end . With a holley it was not as responsive out of the hole. It would lay rubber 100 yards and still do 150mph with the quad. My buddy also runs a quad on his 600hp Buick GS 12.60s:bounce:
 
When you get a chance post up some pics of your boat and motor build. I am planning on going the same route with my ambassador some day. Keep us up to date on how everything turns out.
 
What intake are you planning on running? Single plain likes smaller carbs ( like a 650cfm) and dual likes larger carbs ( like a 750cfm). That's with a Holly carb That's my input. I've heard that quads can make power, if you know how to set them up.
 
I had it out this last weekend. It sure is a torquey motor! Im having a topend issue I need to get fixed yet. I did some tests and found I was running out of gas on topend. I ran a remote tank and all worked great. So Im going to try and get that fixed this weekend. Right now I got 60 mph at 5000 RPM. I had the timing set a little lower for break in. Im going to set it up this weekend and see how it goes.
 
Get you a Holley 750 dual line vacum seconday from some one like Barry Grant or the carb shop in California that has been worked over. They are great for boats! According to the carb shop, you cannot over carb a motor with a vac secondary carb. The motor will only pull what it needs. The secondary side is fully adjustable for when it starts to open and how fast it opens. I ran one on a street legal drag car and it was one of the best carbs I have ever used. Also used one on a 355 in a boat and on a 429 ford in my brothers jet boat. Great results every time!
 
I ran a edelbrock 1410 marine 750cfm on my 383.
Q-junk can make great power if you know how to work them. Left a bad taste in my mouth after one destroyed a motor.

Holley needs tinkering every so often and seems a little colder nature, usually makes the most power.

Edelbrock makes great power, instant starts, and does not require as much tinkering...bolt on and go power.
 
I had it out this weekend. I got the fuel prooblem fixed and I set the timing up. I am very happy with the way it runs. It has a mean idle and hauls a$$. I got about 62-63 mph out of it at 5200 RPM. Thats a great improvement from 55mph with 350. Thanks for all the input.
 
That was my question? What carb are you running. I looked down the throat of my Q-jet and found why the motor expired. It was junked up. NO Fuel. It lead out and cooked the spark plug and motor. My lose.
 
I am running my Q-jet. I changed the secondary cam and put in differnt metering rods. I also had the channel restrictions opened up to allow more fuel. I'm happy with it spark plugs are a nice cardboard brown.
 
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