Best Carb?

[Longroof79]

I do like the simplicity of the Holley, plus it's easy to do jet changes short of taking the whole top of the carb apart. I've run a 600 cfm vac.secondary Holley on my engine for almost 30 yrs. It's been a good carb with very few problems. It's been apart twice during that time for a cleaning and overhaul.

I've always wanted to try a Q-jet for efficiency and better fuel mileage. I had one on my old 305 and it worked pretty well. I'm willing to give it a shot. I don't drag race, auto-X, etc. It's mostly for cruising, so I think the Q-jet will suffice nicely after it's properly dialed in.

My friend had a Holley 750 vacuum secondary carb on his 403 Olds. Years later he went with a 750 Demon, which he likes a lot better. His car runs great with it, and it's in a 4000 lb '77 Cutlass Salon with a BRF 200-4R trans. and 3.42 gears. He's had a lot of problems with the Holley.

 

[vanrah]

Greetings Pontiac GP & all; If Q Jets flowed equal to all four corners wouldn't ya think that the all race cars would use them?? They don't , period. So we disagree on that issue. And for the novice the Holley style is easer to tune. Where we DO agree is the Q Jet does meter fuel across the entire rpm band more accurately providing that you get your primary rod spring to match the cam (NO easy task), the correct rods (all 4, a picnic without fried chicken) & jets to meter that fuel accurately. Can't be done without lots of experience or a wide band A/F gauge. And even then it's no easy task! The Holley style is a very simple carb & always performs better at Wide open (equal flow). It's just the way it is, ya can't argue with 1000"s of engine builders. Well ya can if your so inclined, Ole' Bob.

 

[383_GrandPrix]

Like some of the guys have stated, it's really up to you to decide what carb you want to buy and then tune it accordingly. For my 383 stroker with a mild cam and heads, I was going to run a 750 edelbrock that I already had but bought a holley 870 street avenger carb instead. The reason I did so is because of a fellow car guy who I met through work. He worked on a successful race team for many years and has since had more then a few drag cars of his own. He is a mopar guy through and through although he will wrench on anything and everything. He gave me some food for thought, he reminded me that both Chrystler and GM offered multi carb setups that ranged over the 1000cfm mark on stock, low reving street engines. So as long as you are using a vacuum secondary carb, it will only deliver as much air as the engine will draw, the rest is proper tuning. Now the big thing here is you will need some one who knows how to tune your carburetor, an 870cfm will most likely not be right for your application out of the box.

Engine masters also ran a shoot out of 2 four vs tri power on a 383 chev small block.

 

[lilbowtie]

Without getting into pissing contest so much depends on what kind of carb is going to be used on what and then we get into intake design.
What Vanrah should have said that race carburetors (hp) with 4 corner idle and mechanical secondary's have better distribution. There is so much adjustability (tuning) on both it's just that you need to know what you doing. SO many people start playing with holleys (and Q-jets) and go right for the throttle shaft adj and there goes your transfer slot setting and it gets worse from there.

I'm going to throw in an edit here since this was a response to a post that was removed

 

[rogue_ryder]

https://www.holley.com/products/fuel_systems/carburetors/demon/street_demon/parts/1901

My carb was f'ed on my Olds, and ultimately decided on rebuilding my CCC Quadrajet. Anything else would've required a distributor swap. If I didn't need to do the distributor swap I would've went with the Holley Street Demon 650 CFM. It has the 700R4/200R4 transmission kickdown cable mount and can be mounted on a spread bore or square bore intake manifold. The one linked above has the composite body but for $100 less you can get the all aluminum body. The composite body is supposed to be good for something like a 40*F drop in temp through the venturis vs the all metal carb.

The Street Demon is cheap and probably is the closest thing new to a quadrajet you can buy. The Street Demon design is basically a Carter ThermoQuad (Chrysler used them in the 70s). The driveablity and performance should be very close to a Quadrajet and it's easier to make adjustments to than a Qjet.

Racing style carbs are great at providing plenty of fuel at WFO and making peak power but street driveablity suffers; especially if you're over carb'd.

 

[fleming442]

Vacuum secondaries are okay on auto cars, but when rowing gears, I prefer mechanical (or is that maniacal?).

 

[1badgbody]

Buy a reman'd edelbrock 1405 or 1406 on ebay for $200.00. Put it on the 355, set it, forget it, drive it and sell it for $100-$150 when you put the 427 in and you're done with it. They're two different animals and you will need different carbs. If you have the cash for a 355 and 427 a $200 carb that you can re-sell for almost what you paid for it shouldn't be a big deal. Hey, it's an expensive hobby. Probably save the cost of the carb in gas compared to running a 355 with a 750. Yeah a 355 will run with a 750, might run ok, but it won't run anywhere near as good as having a better matched carb on it.

 

[ham1974]

I went with the 650 hp double pumper.. We see how it does in a couple of weeks when I get the car all together..

 

[MrSony]

I have a holly 750 on my 383 stroker and it ain't too much for mine it should work fine on your 355 or 427

A 383, even a mild one, NEEDS a ton more flow than a 355.

 

[Canon_Mutant]

I would not try to address both builds with one fuel delivery setup. Get a cheap 650 carb to get the 355 going and spend some money on EFI for the 427 later.