what carb for 350 vortec head swap

[inglewatt102]

I got a 1970 350 bored .20 over with flattop pistons and a lunati bracketmaster 2 480 lift cam.I just got some vortec 906 heads to swap out my camelhumps.Was wonderin what kinda carb would be best for my setup.I plan on gettin an Edelbrock rpm intake by the way.I also have some hooker headers on it with a th350 tranny,shiftkit,an 2800 stall conv.Does anyone have a setup close to this?What kinda torque could I be lookin at?Thanx again for your time guys!

[wafrederick]

First,GM does sell the special intake for the Vortec heads.The older style sbc intake will not work on the Vortec heads.Depends what your use is,Edelbrock if for street use and if for drag racing,a Holley.Holley carbs are not good street carbs.

[toddman67]

I am running a similar set up, however I am using AFR aluminum heads and have had great results using the Edlebrock performer carb. I also purchased the calibration kit which allowed me to dial the carb in.
I would not recommend more than 750cfm for a small block. I would also recommend mechanical secondaries and manual choke.

[manicmechanix]

I think the edelbrock is a good carb. From what I've heard people have had the best luck with universal Holley 3310 750CFM. That carb seems to have the emulsion holes in the metering block right for this application and it has the air bleeds sized about right. With jet changes it usually runs OK. I think you would want an electric choke. Maybe a Holley Avenger would be all right.

To get the carb tune right would require a wideband setup like the Innovate. What guys using the wideband tuner usually find is they end up close to a Holley 3310 bleed sizes. So they end up modifying their fancy Demon and avenger carbs close to the 3310 spec. The 3310 doesn't have adjustable main and idle bleeds, but you can drill and tap and put in brass set screws. Also the pvcr are made adjustable for power enrichment. After making these circuits adjustable and using the Innovate wideband, you can get the tune very good. Innovte has an internet forum and they can really help you tune your carb.

Anyway I think an Edelbrock would be a good choice or the holley 3310 or maybe a holley 650 double pumper if you want to go with mechanical secondaries.

[MrPbody]

The Edelbrock intake is far superior to the GM Performance intake.

The Edelbrock carb is a paper weight. We've seen nothing but trouble trying to "tune out" the flat spots and surges. Frederick, whoever told you Holleys aren't good for street had no clue... Holleys can be among the best. At ANYTHING.

The 750 CFM is too large for a 350 not revving to 8,000 RPM. A 650 is much more "in line" with the requirements. The 3310-4 spoken of would be okay, as it has vacuum secondaries, and will allow the engine to tell the carb "how much" instead of the reciprocal... IMO, a well done Q-Jet is the best carb for such an application. Finidng the right person to build the Q-Jet is always the "trick". Cliff Ruggles of Cliff's High Performance in Mt. Vernon, Ohio, is where to go for a Q-Jet.

Jim

[Scrapper]

i'd go with a edelbrock we got one on our wrecker and it will still smoke the tires. it's a chevy 350 bord out 60 over and got a edelbrock intake also with a rv cam.

[toddman67]

I'm not sure of the specs on you cam but can only share my experiences. I started out with a holley 650cfm vacuum sec carb and could not get it to operate properly. It acted like the anchor was holding me back.

I then switched to a quadra jet ('71 vintage from a corvette 850 cfm) and got great response and plenty of power. It took quite a while to get it to idle decently though. On & off the car several times.

I then purchased the Edlebrock performer carb and Edlebrock air gap performer intake. I was able to make all the necessary adjustments on the car with the calibratiom kit. I have good parts in my lower end and I am twisting this thing at 7,000 rpms. I put the chip in my MSD ignition box to keep it there. It idles fine and I don't smell like the gas tank when I'm done driving it.

Higher duration cams are hard to make the car streetable. In my case everything worked out fine.

Keep in mind that everyones situation is different.

[wafrederick]

I have heard of horror stories of Holley carbs,flooding out and many more.One guy was going to throw one on the floor,truck ran like crap and replaced it with an edelbrock which ran better.My father bought a 1966 Chevy II Nova SS,restored with a stock 327 and the holley which it is equipped with is going being replaced with an edelbrock!It floods out and is way too big for this application

[MrPbody]

Well, I can't build the carbs for everyone...(:- Understand it isn't the "nature of the beast" with your Holley problems. It's what we call "last man in syndrome". There's nothing wrong with the design and function of a Holley. It's actually very simplistic and very effective.

I'm happy you're happy with the E-carbs. We can't give them away. But of course, our customer base is a bit different. A 400 Pontiac needs a bit more than an E-carb can provide... Just don't blame Holley for the problems, it's the "mechanic". Too many Holleys out there working perfectly to blame them.

Jim

[toddman67]

I agree totaly with you post and experience. I too have had great success with holley carbs for many years. Unfortuneatly this time is was'nt going to do the trick for my application. I guess my patience or (lack of) gave way after many trials and errors.

It is a good thing that not all of us share the same views on everthing....How boring would that be?
I apreciate your comments.
C-YA,
Todd

[novaboy22]

i run a holley carb on my 72 everyday, its a brand new street avenger 670, ive never had a problem with it. i run a similar setup 906 castings on a 350, magnum 280 cam, weiand stealth air strike manifold, and the 670, 2500 stall on th350, runs excellentwith the exception of 3.08's lol. so when you say holley isnt good for street i would have to disagree, because edlebrock is crap period.