Heavy car carb advice wanted

[ewo357]

Everyone seems to have a different opinion on what type and size of carburetor to go with so let's see what you guys think would work best for my build.?
My main focus is low end torque, throttle response and drivability. Is just going to be a street cruiser that probably won't see 5000 RPMs but of course I don't want to leave any power on the table....

My car is a 1966 Country squire (around 4500 lbs?) with a TKO 5 speed and air conditioning!

The engine is a 445 with stock C6AE-R heads, a port matched Edelbrock F427 intake, hydraulic roller cam (270 276 218 224 .563 .563 110') and shorty headers. 

So far I'm leaning towards a Holley 4150 650 cfm #0-80783 electric choke and vacuum secondaries.

Thanks in advance! I know there are a lot of experts on here!

[ChiefDanGeorge]

Not to derail your thread, but how was the TKO install? I've got a 63 Colony Park with the original Merc O Matic. Be interested to know how your trans swap went.

[blykins]

I'd use a 750, mechanical secondaries.  Choke if you need it. 

I can understand your reasoning in thinking a 650 would give better throttle response, but you can go to an extreme with that, to the point where you critically rob horsepower.  A 445 is a decent sized engine and will fare just fine in both horsepower and throttle response with a 750. 

A Quick Fuel Q-750 would be what I would recommend if you didn't need a choke.  There are some other QFT models that would work well if you needed a manual or electric choke. 

[My427stang]

Agree, 750 is as small as I go, except I'd likely go cheap on that one and go with a stock 3310.  Heavy car, big cubes, the vacuum secondaries will open very quickly when you want them

[jayb]

+1 on the 750 double pumper.  As Brent said, you will be leaving a lot of power on the table with the 650, and the 750 will give great throttle response too.

[ScotiaFE]

Swimming up stream again.

I would recommend a vacuum secondary carb in the same 750 to 800 watts.
The gas mileage with a DP in town will be terrible.
It's just a better to have the VS working in your favor.

Now if you are going full throttle all the time pretty much every time you drive it
then yes use the DP.

[ewo357]

Alrighty then, so far it looks like everyone is saying I should use a 750 (or bigger...?)

blykins why do you like the Quick Fuel over Holley?

My427stang what's the story on the 3310? It looks like there are a few different ones, some 4150 and some 4160, also either 750 or 780?

Thanks for the help guys!!!

[chris401]

http://www.gtsparkplugs.com/CarbCFMCalc.html

Get in the ball park and go from there. Try a Q-Jet if your up to the challenge. There is a big difference between kitting and tuning these carbs.

[turbohunter]

I just installed a QF 780VS for the first time on my 440. I've always used Holleys (I know it's the same company now).
I reeeeeally like the "tunability" of the QF, however don't expect to throw it on and have it run well.
They need tuning. I feel like I had to adjust it a bit more than any Holley I've run (if that makes any sense at all, that's just a general feeling).
However was really able to get it to what I would call a perfect tune. Nice carb.

[My427stang]

So there are a bunch of different 3310s over the years, for the most part though, it is really how much adjustability you need.  There are some booster changes as well, but in general, I haven't seen a small carb like the 750 need much.  Out of the box 3310 4160s are pretty easy to dial in for the street, generally the most they need is fuel level and a/f mixture set, and occasionally like a little more aggressive pump cam.  The nice thing is they are dirt cheap. 

FWIW, on my 445 4x4, I slapped a cheap bare bones 3310, adjusted it and added a blue pump cam and it drives like a dream.  If the truck didn't have a factory choke cable in the dash, it would only be better with an electric choke, but I like having the stock pieces working

[RJP]

There are about 6 or 7 different variations of the 4150/60 3310. The orig 3310 was OEM on 66-67 396 Chevelles and 427 Corvettes. These carbs are 780 cfm due to the down leg boosters, other 3310s [4160] have straight leg boosters and are rated at 750 cfm. If you can find an orig. 3310 off of a Chevelle/Corvette it can be identified by the small tabs on the OD of the primary [downleg] boosters. These little tabs are there only to correct a air/fuel distribution problem associated with the factory GM dual plane aluminum manifold. These carbs are quite valuable to the matching number Chevy restorers. When built properly this OEM carb is a very good running carb as the fuel metering is more precise than the 'aftermarket' 4160 3310 and as the OEM carb had to pass emission testing. Think along the lines of the 4150 735 428 CJ carbs for a good fuel curve, relative good fuel economy and power. To add: I think the 4150 735 CJ carb would be fine for the O/P application. 

[turbohunter]

Couple thoughts on leaving the 650 out of the picture.
Yes low end will be ok but, you can actually feel the engine wanting more as you apply throttle. It feels, umm, not good (for the lack of a better technical term).
The big thing for me was mileage. I actually got worse mileage with the smaller carb. If you've got a big breathing machine pulling a bunch of air through the venturis the signal is very strong and sucks a lot more fuel out of the idle and transition circuit. I proved this to myself by being moron and thinking, "smaller carb, smaller fuel use". Not the case.

[FElony]

Your low end torque "feel" is going to be less carb than rear gear, tire height, first gear ratio, exhaust diameter size, and flywheel weight, none of which we know. Also, know that the C6-R head has a downturned lip at the top of the exhaust port to match production exhaust manifolds that will be a restriction when used with shorty headers. It needs to be removed with a grinder. And patience. And beer.

[cammerfe]

And if you can only come up with two of the three it would be a grinder and beer!

KS

[FElony]

And if you can only come up with two of the three it would be a grinder and beer!

KS

Or, you can step into FElony's World. I wrapped strips of 40-grit paper around my index and middle finger, grabbed a bottle of Jack Daniel's out of the freezer, and used a wall calendar to track progress. I found, through experimentation, that just the right amount of whiskey per hour negated concern with the fact that it took me April and May to expertly port the 7 (!) pairs of C6-R's I somehow acquired. Yes, I am a Pro, and a ground-breaking pioneer to boot. OK, the JD tab was higher than I can get for all the heads combined, but hey, I'm not in this hobby for the money.