Which Holley is Best for Me?
 

I'm about to put a new carb on my truck and am looking for a little advice from the Holley experts (because I'm FAR from one of those) After a lot of reading and talking to a couple different guys that have experience with Holleys, I've got conflicting info. Would a mechanical, or vacuum secondary carb be best for me? I went into this thinking I wanted a 650 DP. But after doing some reading, I'm wondering if the 670 Ultra Street Avenger would be a better choice for a street driven truck. I wanted to hear some opinions or advice on either one of these or even something else that would work better. I'm open to suggestions. Here is a few of the specs on the engine/truck
*355 ci with 9:1 compression
*Edelbrock RPM aluminum heads
*RPM air gap intake
*Comp XE 268 cam
*Auto trans with 2000-2200 stall
*3.73 gears
*5000 max RPM
*Currently running a 600 Edelbrock that performs "ok" I'm putting this carb on my jeep and hoping to find something that performs, and looks a little better for the truck. I'm really wanting to give a Holley a shot.

What are your opinions on a carb for this setup?

Re: Which Holley is Best for Me?
 

Here is the 670
https://www.holley.com/products/fuel...arts/0-86670RD

and the 650 DP
https://www.holley.com/products/fuel...arts/0-76650RD

Re: Which Holley is Best for Me?
 

I'd say it is your choice, as either, properly tuned, should work well with your engine. Congrats for realizing you do NOT need a 750. A 600-650(or 670)is plenty on your engine. Note: all this is just my 2 cents.

BTW: Both those carbs, although pricey, are beautiful.
Sam

Re: Which Holley is Best for Me?
 

Hey, jm, the owner of this (huge business and warehouses of inventory) speed shop--local to me--runs these carbs in the larger cfm on his personal race cars. Just a fyi.
>> http://www.southernrods.com/fuel-sys...es-600cfm.html <<
Sam

Re: Which Holley is Best for Me?
 

All you need is a 600 cfm vac secondary. Like this.
http://www.summitracing.com/int/parts/hly-0-1850s
I prefer the manual choke ones.
Even though you might think a 750 is too big, you might want one. There may be a 383 (or bigger)in your future.
http://www.summitracing.com/int/part...310s/overview/

Re: Which Holley is Best for Me?
 

Yeah a 750 would be way too much carb for this engine combo. Going by the formulas that most use, a 650 or 670 is even a little bit too big.

I haven't ruled out a Quick Fuel carb either. A friend of mine has ran them on a couple of his cars and has been trying to talk me into one for a while now. Are they basically the same thing as a holley as far as tuning?

I guess my biggest question is whether a vacuum secondary or mechanical secondary would be better for a street driven truck. Holley says that the Double Pumper is more for a lightweight car with a high stall. So that has me leaning more toward the Avenger(or other vacuum secondary) carb. Is there any reason to go with a mechanical secondary carb over a vacuum?

Re: Which Holley is Best for Me?
 

With a auto your better off with a vacumm secondary

Re: Which Holley is Best for Me?
 

I'm a pretty savvy Holley user and tuner, but for a street/strip vehicle, I'd seriously consider the Edelbrock. Usuallly cheaper to buy, cheaper to tune, and cheaper to rebuild. Quite driveable with the electric choke.

I'm not a 600 cfm carb guy, I find the 750 runs better on pretty much everything from mostly stock to high perf. I've got a 1040 CFM Barry Grant (pre-Demon carb) on my Camaro and it's excellent at everything but cold start. But I have ditched Holleys on most everyhing else. I have a Jet Q-jet on the Jimmy, a 600 Edelbrock for my 69 short bed and a 750 on my 360 powered CJ5 and my 350 ci ski boat.
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Re: Which Holley is Best for Me?
 

you'll get better performance with the double pumper, better mileage with the vac. sec.

Re: Which Holley is Best for Me?
 

You asked, "Are they basically the same thing as a holley as far as tuning?". Not having actually used one myself, I read about them and that tells me they are simpler to tune than the Holley. But they surely look like the Holley, don't they? I'm convinced from my reading that they would be my choice over Holley were I to buy either. [I am a dedicated quadrajet user, as I had to spend so much time studying them and all their functions in order to service our customers' voluminous needs over the years; their problems were caused mainly by lack of q'jet knowledge on the part of mechanics honestly attempting to fix customer complaints.]

Your biggest question is an easy answer: Buy the vacuum secondary! Just my 2 cents, again. But I think I'm right!
Sam

Re: Which Holley is Best for Me?
 

670 Ultra street avenger is the way to go. Much easier to tune than a double pumper. And you can achieve great fuel mileage if your willing to put in the work. Pick up David Vizards book on how to super tune and modify holleys, its a great help book.

Re: Which Holley is Best for Me?
 

I would get this best holley series carbs period. run great right out of the box

http://www.summitracing.com/parts/qft-bd-1957/overview/

Re: Which Holley is Best for Me?
 

Not necessarilly!
Back 35 years ago I had a 70 Chevelle. LS6, 4 speed and 4.10 gear.
Factory 780 cfm vac sec carb.
Swapped my buddy for his 750 dp that he had on his 454 with turbo 400. . Figured it would be better considering people said to run a vac sec with an auto and a dp with a standard.
Found out the factory vac sec carb was the better choice for my 454. And the better choice for his 454 too. He sold the dp and got a vac sec carb awhile later.
So lesson learned was go vac sec unless you have steep rear gears and/or a real high stall.

Re: Which Holley is Best for Me?
 

Have this on my stroker. Looks great...runs great!!

Re: Which Holley is Best for Me?
 

I agree with with what most guys here are saying. A 600cfm works well with a close to stock or mild 350. I have a 750 double pumper on mine, but I wouldn't consider it stock or mild (383 stroker). As for Edelbrock vs Holley, I think it's just what your used to and comfortable with. I know Holleys better (have had them on 5 previous cars), so for me their easier to tune.

Re: Which Holley is Best for Me?
 

Your engine is just a very complicated air pump. To figure out which carb will work best use the following formula :Carb Flow rating in CFM= DISPLACEMENT (cubic inches) x RPM / 3456
So, for your 355 cu in motor, (355x5500)/3456=566 CFM. So a 600 CFM carb would give adequate performance but a 670 is the largest you should run. And, before all you magpies start chattering about density altitude, volumetric efficiency and all the rest of that stuff only racers care about (like elevated compression ratios);the formula is for a stocker that is just a daily driver all of that boy racer stuff dissipates like a fart in the wind and leaves no lasting impact.

Re: Which Holley is Best for Me?
 

I have a vortec 350 with comp XR258HR and I'm using a rebuilt Holley 670 Street Avenger I purchased National Carburetors on ebay. I was a bit hesitant but it was only $270 and they had excellent reviews and a warranty so I took a chance. Slapped it on and was tearing up the street with no adjustments. Carb looked beauityfull when I opened the box.Still haven't touched it. Holley also sells rebuilt units, so if you looking for a deal check online.

Re: Which Holley is Best for Me?
 

What makes you think your engine is done at 5,000 rpm? With that combo, you should be good for close to another 500-1,000.

I love going against the grain. With that combo and those gear (a little stall), I'd run a DP. I had a 6,000 lbs 3/4 ton with a 468 and ran a 650 dp. Freaking loved it.

Granted......I know nothing about Holleys and this is just a guess.

Re: Which Holley is Best for Me?
 

If you call Holley and talk to the tech line they will give you advice and recommend one. If you purchase it thru them they will back up the advise if they were off and you needed a different cfm. I know this from experience. Same price as summit too.

Re: Which Holley is Best for Me?
 

^^^Ha I know better than that. Ive read alot of your posts. I was hoping you would reply.
What size stall would you recommend?
Why would you go with a DP over a vacuum sec carb with this paticular setup? Everyone including holley keeps telling me to stay away from a DP. But no one has really explained to me why?? I'm really just wanting to learn this stuff to make the best decision.

Re: Which Holley is Best for Me?
 

A quick fuel slayer, ss, or hot rod is just another 4150/4160 variant - standard holley parts work and they are tuned just like any other square bore holley. with qf you get more for your money, check out the hot rod 680. vac secondary with four corner idle and adjustable metering blocks, so they have screw in idle feed and pvcr jets and also screw in air bleeds.



http://m.summitracing.com/parts/qft-...obileSwitchYes

Re: Which Holley is Best for Me?
 

I will lose the vacuum argument every time. It's always been a general rule of thumb that light and or 4 speed = DP. Heavy and or auto with lower stall = vacuum. It'a mainly because you motor cannot process more fuel than it needs period. A vacuum carb will allow the motor to decide and pull in the fuel needed at the right time based on the vacuum the engine is producing.

With that said, I like double pumpers. I like to know exactly when that secondary will open. I can feel the linkage come up on the slip bar that opens the secondaries so it's easy for me to stay on the front side of the carb as long as I want to. Makes no sense but that's how I roll. Granted, my last ride was an M-22 with 3.73 gears. Also had a roller 454 with 3,000 stall so it worked pretty easy. Just go with a little 670 and be done with it.

Side note: I have had great luck with Quick Fuel and Proform. They are (or were) sister companies and use many of the same castings with different color anodizing base on what door it went out and what name was one it. Seems to be really good quality shelf stuff. Just stay away from PROCOMP!! Some of the worst castings and quality control I have ever seen.