383 Carb Choice

[Montclaire]

850 DP is too big of a carb. You are right, most 4spd cars got a Holley. I would probably swap on a used dual plane and tune up a 600/650. I know everybody likes to say big cfm numbers and "double pumper" but you're probably just washing down your cylinder walls and in PA you're paying over 50 cents per gallon in tax, so....

 

[oldbee]

Boy those old dbl-pumpers sure sound nice don’t they? IMO on the street, and for street driving, a vac.sec. 750-780 is just fine.

 

[pentahead]

Hey everyone, it's winter and I know most of us are going stir crazy. I've been rolling around the idea of a new carb for my Charger. I currently have a mild power built 383. It was my dads car when he was a teenager and he popped an 850 double pumper and a cam in it. Today, I still jave the same cam and carb on there. It runs and runs well but down low its a little rough to try and tune. Thats also probably due to the single plane intake I tossed on there.
Anyway, in my research I'm finding that there are a ton of mixed opinions out there for what carb is best for a 383. Some swear by the 850, others a 750 and even 650s. The double pumper seems to be the go to choice for 4 speed cars, which is what ive got; but there are plenty who stand by edelbrock or thermoquad.
I know it ultimately comes down to the intended use of the car but I figured that anyone who's looking for a general tech discussion to exercise their brain could weigh in on what carb they like the best for 383's. It's all a learning experience so any input is welcome!

I run a Tq on my 383 w 484 purple and 4speed...no problem

 

[pentahead]

Thermoquads are nice, that is, if you can find one that is in good condition without significant wear on the throttle rods, most are missing the coating and therefore cause issues with vacuum leakage around the throttle rods. But, if you can find one, they are nice, because of the vacuum secondary's, they are good on fuel until you put your foot down, and nothing sounds like a thermoquad when the secondary's open up! Also, once you tune them in, they never change. I do know they perform much better with ethanol free fuel and evaporate fuel faster than most carbs when they sit, they do have a lot of open venting. I have tried several different ones until I got one that worked properly, so not trying to discourage you if that is the direction you want to go, just be aware of the pitfalls of resurrecting a thermoquad, it can be a challenge.

 

[Hankohop]

hey! long time no follow up. I did actually downsize to a 750 vacuum secondary and it's a hell of a lot better. sorry everyone for falling behind! Wound up moving the car into a garage and have been mostly doing bodywork. Still need to tune the thing but you were all right 850 double pumper sounds super macho but in reality, the smaller 750 works much better.