Quick Fuel 650 CFM for my 66 Coronet

[mtbase]

The big block 361 was squashed in 1966 when Car & Driver wrote it off as a "boat anchor" in a magazine article. Same block and crank as a 383, but a smaller bore. That was the end of the 361ci's run in a car, then relegated to the Mopar truck line. My Coronet 500 came with this 361 and I rebuilt it AND the Carter B&B carb (2bbl), made it run also. I'm understanding what Car & Driver complained about...just doesn't have that "kick". My car is almost as original as I could get it to, with the exception of adding dual exhaust, dual master and 15" wheels. I located a period correct 4bbl manifold, made it pretty and now I want to put a current technology carburetor on it. I'm really about originality, but I think anyone would make the relatively minor changes that were made and under consideration.

Thinking about the Quick Fuel 650 and don't know if it's enough or too much...should it be a double pumper? Would anyone care to offer an opinion?

 

[747mopar]

I think a 650 would be fine, rpm's and displacement are what brings about the need for big carbs. If I'm understanding you correctly it's pretty much stock so no high rpm's are in store and you have a relatively small displacement so yeah, why not.

I will disagree with the common thought process of using vacuum secondaries on heavy cars. If you plan on just floor boarding it then yes vacuum secondaries but if you know your motor and know how to drive a car then double pumper all the way. I love my QF DP.

 

[Don Frelier]

650 is good.
But a 361 has the best wear index of any motor ever.
If you want some kick then you will have to move away from the stock setup.
Over 9:1 compression and a roadrunner cam and change the exhaust manifolds to HP for 68-69. Then it will move.

 

[PurpleBeeper]

To answer your question, a 650cfm carburetor is just fine. Personally, I don't recommend a double pumper anything UNLESS it's a high rpm manual transmission car or has a massive stall converter. Double pumpers kill gas mileage. From my own personal testing on a 440 with 3.55 gears (4-speed)
650 double pumper --> 6mpg city/8mpg highway
750 vac secondary --> 8mpg city/10mpg highway
Six Pack --> 10mpg city/12 mpg highway

I was very careful to drive the car the same with each carb setup. I ran these all back-to-back over about a 2 month period changing only the carb (+ intake for the six pack). If you have the cash, they do have some aftermarket six pack intakes that will fit the 361's...just sayin'

 

[747mopar]

To answer your question, a 650cfm carburetor is just fine. Personally, I don't recommend a double pumper anything UNLESS it's a high rpm manual transmission car or has a massive stall converter. Double pumpers kill gas mileage. From my own personal testing on a 440 with 3.55 gears (4-speed)
650 double pumper --> 6mpg city/8mpg highway
750 vac secondary --> 8mpg city/10mpg highway
Six Pack --> 10mpg city/12 mpg highway

I was very careful to drive the car the same with each carb setup. I ran these all back-to-back over about a 2 month period changing only the carb (+ intake for the six pack). If you have the cash, they do have some aftermarket six pack intakes that will fit the 361's...just sayin'

They only kill mileage if you use them otherwise it's the same thing. I can feel my secondaries in the pedal and they never get used in daily driving but sure add to the fun factor... 19 mpg too. O.K. I'm cheating with 2 extra gears and a manual plus crank it to 6,000 rpm lol.

 

[mtbase]

My "days of thunder" are over, so no rubber burning me, but I'd like to think I could. It is an original factory 4 speed car with an 8-3/4", one of 373 made ( because of the 361, that why it stays as a 361). I also have a 66 Barracuda with a factory 273 4 speed and while I've done little to the car...it is a zippy little thing. The Coronet 500 has had stupid money put in it and the Barracuda would leave it in the dust. With as much time, effort and money as I have in it, I have to go further to give it dignity. So, it's not about gas mileage, or impressing anyone else.....it looks great and I want it to feel great.

 

[BeatersRus]

what rear gear are you using?
might could get more zip with a simple swap.

 

[mtbase]

It's a stock rear end, I'm open to ideas.
The carb replacement is also motivated by the existing old technology and temperamental "spring type" chokes. That Carter carb was never popular and it's dam hard to find. I'm thinking that the new ones are more reliable, responsive, fuel efficient.

 

[Don Frelier]

My charger came with a 500 CFM carter AFB. With the small primaries it was very responsive and tuned properly it would yield fuel mileage as good as you could get.

 

[mtbase]

My charger came with a 500 CFM carter AFB. With the small primaries it was very responsive and tuned properly it would yield fuel mileage as good as you could get.

On a 361 with a 2bbl?

I don't even know what the CFM on mine is. I know that the 67 'G' code car had a 383 with a 2bbl...can't imagine it running much stronger. It's bored .120" over the 361.
I had a Cater 600 on a 69 Dart 340 and I could never seem to improve on it. Carter's are good

 

[Don Frelier]

383 9.4:1 906 heads 68/69 manifolds with a.455 Mopar cam