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View Full Version : Correct Holley Carb Size



Emo69SS
02-03-2005, 04:54 PM
I'm looking for a little guidance before I purchase a new carb. I have a 383 stroker, vortec heads, rpm performer manifold, Comp XE 268 camshaft, 700R4 trans and currently an Edel. 600cfm carb. The car is really falling down (not living up to it's potential) at WOT and I'm fairly certain that the carb size is the problem. The current carb is the one that the engine builder used and I haven't been happy since day 1. I am certain that I want to buy a Holley. I spoke to the tech guys there and they suggested either a 650DP or the 670 Street Avenger. Some of the carb comparison articles I've been reading such as one in Chevy High Performance indicate that the fuel monitoring in the Holley's is so good that the 750 was their choice in the test on a Smeding Performance 383 stroker. Any input would be greatly appreciated. I would rather base my decision on real owner experience than what a math equation says I should have for a carb. Thanks!

Eric

HILROD
02-06-2005, 03:26 PM
I personally think a 750 holley would be great. I like vacuum secondaries. A double pumper can be trouble to tune especially with an auto trans. FRANK.

zbugger
02-06-2005, 08:16 PM
The 750 would be a good choice. If it's a street car, try the vacum secondaries. If you drive it occasionall, such as on weekends, the DP would be fine. You could also check out the Barry Grant Speed Demon carbs. I hear they're pretty good.

ProdigyCustoms
02-08-2005, 02:06 AM
Your 600 is killing you. not only is it small, but those Edelbrocks make no power. Smooth as glass, just no power. I know there is a big vacum secondary craze right now, and there is some tuning possible, but I have yet to see one that can touch a DP. Out of the box, a 750HP will be a bad boy for your motor.

toofun
02-08-2005, 07:10 AM
I think it is safe to say you'd better go with the 750 holley. YOu could go with the Mechanical secondaries, but by the sound of the input here, I would go with the Vacuum secondaries to stay on the safe side. Hate to say I told you so about the 750 but............TOLD YOU SO!! Hey gotta bust your balls EMMMMMOOOOOOOO!!!!!

Call me at work

Emo69SS
02-09-2005, 04:12 PM
Thanks for the input everyone. I figured the answer was going to be the 750 but just wanted to hear it from the experts. The car does and will spend 99% of the time on the street and it has the auto trans so the vacuum secondaries are probably the way to go although Prodigy is right that there is nothing better than the throttle response out of the mechanical 750DP.

TooFun, thanks for busting my balls but can I remind you how the 600 got on there in the first place........ I'll call you at work Thursday morning

Emo69SS
02-09-2005, 06:08 PM
OK, the carb size has been established. I now need opinions about 2 specific Holley carbs I'm looking at. The first is a 4160, 750 cfm, model # 0-3310S, vacuum sec., etc. The second is a 4150, 770 cfm, street avenger, model # 0-80770, vacuum sec., etc. My questions are:

1. Is the 770 too much carb for the engine?
2. The 770 has 4 vacuum ports(pcv, power brake, spark, accessories) and the 750 doesn't specify whether it also has the 4 vacuum ports. I'm sure this is a stupid question, but should I be making my decision around the vacuum ports?

Does anyone have any opinions about either of these carbs specifically or opinions about which carb would be the best choice? I'm not aware of what the benefit of the Street Avenger Series is versus the Universal product line that Holley offers. Any information would be appreciated. Thanks again!

Eric

WELTERRACER
03-11-2005, 10:25 AM
Vacume carbs only give as much fuel as the engine needs.. Thats why they work so good..

THe 770 is a great carb and will work awsome on your car.. Vacume secondarys work way better on street cars with Auot trannys.. I found out the hard way..

BTW.. my sbc with a vacume secondary 750 ran 12.80s with a 2500 stall and turbo 350 pulling 1.80 60foot times with street tires.. LIKE I SAID THE VACUME SECONDARYS WORK GREAT

Rick Dorion
03-11-2005, 11:31 AM
And then there's the 700 DP :)

gmachinz
03-11-2005, 09:31 PM
I vote for the 750 vacuum secondary Holley as well. I use one which I've gone through extensively. You can pm me for specs but basically, I had a weak upstairs until I went through it. You will still need to tune the heck out of it out of the box. I experimented with various springs-they determine at what manifold vacuum reading they will open-allowing more fuel (also why there is always a slight hesitation when you mash it-it's supposed to do that.) and found the plain one worked the best. And, I installed a 50cc pump kit (no sense in going with bigger jets, nozzles only to keep with the stock 30cc pump kit on it) to ensure extra fuel upstairs, went with progressively larger jets, squirters and nozzle sizes, too. For throttle response, you want to keep with the dog-leg boosters-the 90/degree ones offer less than ideal response for the street and are more suited for competition use as in the DP line. Finally, I would swap to a secondary metering block and remove the metering plate that is on it now-that way you have a little more tuneability with respect to jet changes for the secondaries. Oh, and I kept with a 6.5 power valve. You may want to change yours based on manifold vacuum present-I run about 16-18 inches @ idle. Long and short of it is I have a $150 carb with about $150 worth of mods I did myself. It works great for me. You may want to think about using an A/F ratio gauge w/a three wire (think 1996 Chevy 1/2-ton truck :) )O2 sensor for added tuning ability. I stay in the 13:1 range and for my combination it has worked out great at all RPM ranges in my SB-very consistent fuel delivery. I also use a Holley regulator set at 8 psi @ idle and it creeps to around 11-12 @ full throttle under load. -Jabin

Emo69SS
03-13-2005, 02:35 PM
Welterracer-
Thanks for the input. I seem to be leaning more toward the 770 at this point. Only concern I have is that I am not oversizing the carb on the 383 stroker engine. What do you think about that point?

Eric

Emo69SS
03-13-2005, 02:37 PM
Rick- That was my original plan, but I want the vacuum secondaries and with the DP you get manual

Eric

Emo69SS
03-13-2005, 02:37 PM
G-
PM sent

WELTERRACER
03-13-2005, 03:34 PM
770 isnt too big for that engine.. 383X6500rpms=2489500 devided by 3456=720CFM carb...

I run a 750 on my 355 spinning 6500rpms.. and works awsome.. bigger motor needs bigger carb..

Kevin@W2W
03-14-2005, 01:29 PM
In my experience the Edelbrock carbs are good for cruisers. If you want performance stick with a Holley or a BG.

The 770 avenger is a very good carb for that motor and will not be too big due to the vaccum secondaries.
One thing to consider is the avenger comes with a few extra goodies that the 3310 does not.
Like, the quick change cover for the secondary spring and a few other things.

Personally I have always had very good luck with the 3310 and the 770 over the years when I don't use a Barry Grant.

Good luck:)

SatisTraction
04-26-2005, 09:14 PM
talk to a pro about it

http://www.pro-system.com

his are the best

383
04-27-2005, 10:30 AM
I run a 600cfm Edelbrock on my 383 stroker with Edelbrock rpm package all the way, but since iŽam never satisfied i bought the Holley 3310 750cfm carb but have not put it into place yet.
If you want i can keep you all posted on the result.

vanzuuk1
04-27-2005, 06:26 PM
383 , Ive got the 670 avenger on my 383 and it runs good but I dont have much to compare it to. Let me know If i should experiment with something bigger when you install yours.

Emo69SS
04-28-2005, 07:43 PM
I ended up buying the 770 Street Avenger but haven't intalled it yet. I just got my new TV setup because I have a 700R4 so I'll get it in soon. 383, I'd be interested to hear how you make out. I'll post my results also. Thanks to all who helped out!

Eric

CAMAROBOY69
04-29-2005, 03:58 AM
I agree with everyone here about the 750 Holley.
I am running the 750 Holley Double Pumper 0-4779C with manual secondaries on my 383 with cast iron heads. And it runs good enough to get me into the mid 12's. 12.66 to be exact. Yes cast iron heads too.
I started out with an Edelbrock 600 and what a joke. Just starved the engine to death and never ran correctly so I bit the bullet and bought the correct carb. I also fouled plugs every 2 weeks until I put the 750 on.
For the record I was never into Holleys until I bought this carb! Now I am a believer. :hail:

Rick Dorion
05-02-2005, 06:21 AM
Can someone elaborate on WOT vacuum and how it relates to carb sizing? I have a 355, 180 ProToplines, 1 3/4" Hedman's, reworked 700DP and see a vacuum reading of 5 at WOT.

chicane67
05-02-2005, 11:58 AM
5" at WOT is perfect.

If I didnt have a hard drive failure, about a month ago, I had an article on just that. But, now I have to find it again on the net. I'll try and get back to you on this Rick.

Rick Dorion
05-02-2005, 04:23 PM
Appreciate it, Tom. As I explained to the trooper yesterday, I was so sorry about my speed as I was watching the Innovate and vacuum gauge! Used up my get-out-of-jail card on that one.

383
06-12-2005, 09:39 AM
I`ve just installed the 750cfm 3310c holley and i must say so far so good, runs pretty well with just the basic adjustments (on my combo)

CAMAROBOY69
06-13-2005, 04:39 AM
Glad to hear you enjoy your 750 purchase. :)
I prefer the Manual secondaries but the vacuum secondaries will work too. :yeah:

JLM
06-22-2005, 07:20 AM
I'm not very knowledgable when it comes to carbs. Can somebody explain exactly why it's better to go with a vacuum secondary on an auto verse a mechanical secondary?

I'm in the market for a new carb for my setup. 462cid, 428 HO cast iron heads, headers, healthy cam. I want to go with a holley vs the POS edelbrock I have now. Any suggestions? 850hp perhaps?

vanzuuk1
06-23-2005, 03:16 AM
I have got to leave for work but I will give you the readers digest version.

A vacuum secondary carb will be more forgiving if your clumsy on the gas pedal, it will run smoothly and give you good throttle response over a wide range of conditions.

The double pumper ( mech. sec.) will dump more fuel and bog if you stomp the pedal.It also needs to be setup a little more carefully to run right.