What size carby

-
douglas340

douglas340

Well-Known Member
Joined
Apr 13, 2011
Messages
204
Reaction score
24
Location
Brisbane, QLD
Hi all, just wondering what size carby I should be running on my 340?
Engine mods are:
Ported Eddie heads, crane 1.6 rockers, Head flow numbers.
LIFT--IN/EX IN EX...
.600"--276.6/218.6 34.4 33
.650"--283.5/221.6 40.3 36
Manifold is a port matched victor junior 340, cam is a comp solid roller P/N XR286R.
Engine comp is 10.8.
I'm running a secondhand 850cfm race demon on it now that's been on it a little over 8 months. I think it's a bit worn out as it keeps going out of tune, so I'm going to treat myself and buy a new carby.
So I'm wondering what size carby will suit my engine?
The dyno pull was before I installed the 1.6 ratio rockers.

20180721_123807.jpg


20190105_160945.jpg
 
Why not try efi, I heard great comments on the set up. ''like if you thought it was fast before now it is scary fast and no more pumping the pedal to keep it going. You could use a 400 hp set up.
 
Because he asked what “carb” to use, not what efi to use.

OP, are you happy with the way it performs other than being worn out falling in and out of tune?
Is this track only?
Gear ratio?
 
rumblefish360 said:
Because he asked what “carb” to use, not what efi to use.

OP, are you happy with the way it performs other than being worn out falling in and out of tune?
Is this track only?
Gear ratio?
Click to expand...
Its mainly weekend cruises and some drag racing every now and then.
Gear ratio is 3.5. It performs good!! But not sure if it will be better with a different size carby?
 
Go for a 750.
IMO, the 850 sounded like it was on a track only car.
 
douglas340 said:
Hi all, just wondering what size carby I should be running on my 340?
Engine mods are:
Ported Eddie heads, crane 1.6 rockers, Head flow numbers.
LIFT--IN/EX IN EX...
.600"--276.6/218.6 34.4 33
.650"--283.5/221.6 40.3 36
Manifold is a port matched victor junior 340, cam is a comp solid roller P/N XR286R.
Engine comp is 10.8.
I'm running a secondhand 850cfm race demon on it now that's been on it a little over 8 months. I think it's a bit worn out as it keeps going out of tune, so I'm going to treat myself and buy a new carby.
So I'm wondering what size carby will suit my engine?
The dyno pull was before I installed the 1.6 ratio rockers.

View attachment 1715353813

View attachment 1715353814
Click to expand...
Throttle shaft bushings go out quick on those...gives lean wot and lean spikes at idle out of nowhere...find yourself resetting the idle over n over.

Get a 750 cfm carb, dbl pump... any brand you like.
 
MOPAROFFICIAL said:
Throttle shaft bushings go out quick on those...gives lean wot and lean spikes at idle out of nowhere...find yourself resetting the idle over n over.

Get a 750 cfm carb, dbl pump... any brand you like.
Click to expand...
I've been told the same thing about them, but it was after I put it on unfortunately lol
 
I have a Edelbrock 1813 Thunder series AVS 800cfm, electric choke available if your interested. Bolted on my engine but never had fuel in it. Decided to go fuel injection so off it came.
 
That's a lightweight car right?
my pick is Spread-bore, it will be a lil easier to drive at low throttle settings around town, especially if it's a manual trans. What size? IDK; any between 500 and 850. How about a Goggle-Valve750?
 
I can't see the 850 holding you back much. Maybe if it was a drag only car there might be little to gain.

First I'd check the vaccum at full throttle run. And make sure the breather ain't a restriction. And go from there.
 
Aussie
I agree on the spread bore vac sec (for street/strip auto) (dbl pumper for strip or stick)
but run what you can get
can you not bush your current carb?
I'd spend my money on a B3 kit to make that cam happier
 
The intake is a square bore. I’m not a fan of bolting on an adapter just to run a TQ.
 
Put a nice holley 770 avenger on it, vac secondaries electric choke, or a 4779 750 Dbl pumper with 4 corner idle.
 
Which ever carb you decide on getting, make sure it’s a right hand drive version.
 
You must log in or register to reply here.
-

Back
Top