What Carb do you guys run on the 383??

[67chevemall]

I need help chosing a new carb.
I had a 600 holley for years that was ok
The Edelbrock 1406 just isn't cutting it. I don't like it.

Any pics or suggestions would be great......

I like the demon series.....
And the 4150 Holleys look good too....

anybody

[70rs/ss]

Just for a driver? 750 edelbrock. I plan a 750 double pumper, but mine is in a "fun" car, not my DD. What's wrong with the 1406?

[muscletrucks]

The best carb for the torquer 383 is a Holley 670 Street Avenger. This with a dual plane intake and the numbers show you can't do any better. It hits the sweet spot. Rodney

[Billla]

Originally Posted by 67chevemall

I had a 600 holley for years that was ok
The Edelbrock 1406 just isn't cutting it. I don't like it.
I like the demon series.....
And the 4150 Holleys look good too....

CFM = ((CI x RPM)/3456) x VE, if you figure 383 HP then you don't need more than 600 CFM until past 6000 RPM. You'd have to turn it to 8K to need 750 CFM.

There's nothing wrong with the 1406 - if it's not "cutting it" then it's not working, configured or tuned correctly. I agree that the Edelbrock Performers, Holley Street Avenger or Street Demons are the best choices for a daily driver.

A mechanical-secondary carb is a racing carb, not a street carb. You give up driveability and fuel economy for instant acceleration performance - if that's a good trade-off, then cool - otherwise tune what you have.

[HoupPhotography]

X2 ^^^

[67chevemall]

I have tried everything I can to get it to run nice again.
It has been sitting for a few years now so it is even harder.
I thought about taking it to the engine shop down the road, but hate
to leave the truck anywhere.
I think it could be the dizzy and timing more then the carb.
Just want to get the right carb on there before I take it in.
I can flat bed it to a place next town over where they would
tune it up nice, and dyno it all on a Saturday where I can "hang out"

I could tune the 1406 but I like the holleys much better.Want to go back.
I have a brand new 1406 I would trade somebody to get me going.

Your right I don't need Mech Sec. at this point.
The truck is just for Sunday runs for now.
What is the holley Vac Sec # for 650 carb?

?? spring is here and I'm still in bed: go time

[Billla]

If you must have a Holley, then the Street Avenger is your carb.

Always timing, then carb for tuning...

[muscletrucks]

Like I said.......................

[Billla]

Originally Posted by muscletrucks

Like I said.......................

Hey - didn't mean to not give you your props! Exactly like the man said in a prior post

[muscletrucks]

No problem, your tops with me!

[wibilly]

i never cared for holly carbs but love my street avenger

[BarryB]

I am planning on putting a 750 spread bore Holley on my 383 stroker motor. I might have to jet it down some but what is the point of having a stoker if your going to putt around in it.????

[67chevemall]

I have a weiland square bore manifold. Would this be the problem with the 1406?
I took a few of your guys advice and bought the bigger thinker gasket from summit.

I put the carb on last night.
I am going out to blow out all the fuel lines and get some fuel up there.
see what happens this time.
It has been a while.

I like the looks of that avenger. thanks for that tip.

[bryanw1968]

I am not a holley guy anymore but when I had my 383 I ran a 780 and it was perfect!!!
A think a 650 is just not enough carb especially when we're talking about holley's.
If you're talking a Demon it's different. They underrate their flow numbers quite a bit. My BG650 DP flows 725cfm. I attempted to run a BG750DP on my pretty punchy 355 and it was WAY too much carb. My .02 cents......

Good luck,
B

[BurnoutNova]

Originally Posted by Billla

A mechanical-secondary carb is a racing carb, not a street carb.

sort of, your right about fuel economy. i'd say some machanical secondary/ double pumpers are racing carbs. the ones with no chokes, and huge acelerator pumps and/or dominators. alot of cars came with them from the factory, and the one on my nova is a out of the box 650 DP, and it runs around great on the street. no driveability probleoms at all. it does like the gas though.

[Billla]

Originally Posted by BurnoutNova

sort of, your right about fuel economy. i'd say some machanical secondary/ double pumpers are racing carbs. the ones with no chokes, and huge acelerator pumps and/or dominators. alot of cars came with them from the factory, and the one on my nova is a out of the box 650 DP, and it runs around great on the street. no driveability probleoms at all. it does like the gas though.

Even the ones with chokes are really racing carbs; the driveability problems of quickly-opening secondaries get covered up by a big shot from the accelerator pump.

The most common "big" carb was the Holley 780 which was a 4150 vacuum secondary carb with a secondary metering block in place of the standard plate - like a 3310 today. Even the LT-1/ZR-1 used this carb. As far as I know (and I ain't the expert ), the only factory Chevy mechanical secondary carbs were used on the 302 cross-ram and the ZL-1/L-88...not really street engines ;-)

As noted, it's really just a choice - if immediate accelleration is your bag, then that's the one area where a mechanical secondary carb will shine.

[b&a72]

I am running a 750 double pumper on mine as well and love it! Well before the teardown at least.

[chevy72blu]

Originally Posted by Billla

Even the ones with chokes are really racing carbs; the driveability problems of quickly-opening secondaries get covered up by a big shot from the accelerator pump.

The most common "big" carb was the Holley 780 which was a 4150 vacuum secondary carb with a secondary metering block in place of the standard plate - like a 3310 today. Even the LT-1/ZR-1 used this carb. As far as I know (and I ain't the expert ), the only factory Chevy mechanical secondary carbs were used on the 302 cross-ram and the ZL-1/L-88...not really street engines ;-)

As noted, it's really just a choice - if immediate accelleration is your bag, then that's the one area where a mechanical secondary carb will shine.

The 4150 780's are great carbs... I had one built by a guy I know (modified bleeds, air horn/choke tower delete, etc ect) for my BBC. Suposedly they will flow 810 cfm. They are pretty sought after as corvette restoration carbs.

[Billla]

Originally Posted by chevy72blu

The 4150 780's are great carbs... I had one built by a guy I know (modified bleeds, air horn/choke tower delete, etc ect) for my BBC. Suposedly they will flow 810 cfm. They are pretty sought after as corvette restoration carbs.

Most definitely - I have 3 of these; one LT-1 original from 1970 and two reproductions that were available directly from Holley in the early 80's. I also have the LT-1 intakes to match; 1 original with a late '69 cast date and two reproductions available from GM also in 80's.

The original stuff is going into a factory correct (but with a refit roller cam ) LT-1 I'm building...slowly...for my '69 Corvette. The others I'm just holding in trust for the right project. I love this setup for a hot 425+ HP GEN I.

[BurnoutNova]

what do you mean by lt-1/zr-1? im very farmiliar with the 70-72 lt-1's but the only zr-1 ive heard of is the 90's corvette zr1

is there another?

[Billla]

Originally Posted by BurnoutNova

what do you mean by lt-1/zr-1? im very farmiliar with the 70-72 lt-1's but the only zr-1 ive heard of is the 90's corvette zr1 is there another?

A bit OT - but yes, there is!

The original ZR-1 was a special purpose 1970 LT-1 Corvette that required mandatory options that were typically only available with the L-88/ZL-1; HD brakes (J50/56), HD suspension, HD transmission (M-22) and radio delete. It could not be ordered with power windows, power steering, A/C, rear window defrosters or wheel covers.

A ZR-2 with an LS-7 454 was planned but never released.

[piecesparts]

Everyone has their taste in carbs. Holley supports the vacuum secondary carbs BECAUSE that is what they sell. Edelbrock sells the mechanical secondary carbs and so does Carter. You will note the Carter AFB and Edelbrock series carbs are the EXACT same thing, just different names on the outside. Both are made by an outside company and marketed by the appropriate supplier. Demon is great in some people's eyes and others have had nothing but trouble.

I am presently running an Edelbrock Thunder carb AVS (650 CFM---not the 600 CFM size that the 1406 carbs are). The step up made the 385 engine work real well in daily driving. I had a 750 carb for a short period and suffered the problems of too much cam and not enough gearing (at that time) and deinitely too much gas for daily driving. Since then I have changed to a 3.73 gear ratio and the 650 works that real well up to about 5000 RPMs. With the OD tranny, I don't even phase that RPM and the speedo is pegged out of site. As for the mechanical secondaries--the adjustment of the carb is the game not just bolt the thing on and watch it work. I run a 385 stroked motor with a dual plane intake, Comp Cams roller valve train, 700 R4 tranny, 3.73 posi and I get 15 MPG. I don't consider it bad for a truck that can eat a Mustang and burp the waste parts out.

I personally would look at a 750 carb, IF and only IF, you had a light weight vehicle---with a low geared rear end and plenty of RPMs in your cruising. Otherwise you will experience a lot of bogging at stoplights and lousey gas mileage. Just ask any distributor (Holley, Edelbrock, Carter, or Barry Grant) and they will support this. I did ask them and they all talk the same line in figuring carb size. You wnat to keep the air velocity up in your intake or the package you pick for performance will suffer. The slightly smaller CFM rating on a heavier truck is desired.

Once again everyone has their own taste.

[Billla]

Originally Posted by piecesparts

Everyone has their taste in carbs.

Holley supports the vacuum secondary carbs BECAUSE that is what they sell.

You wnat to keep the air velocity up in your intake or the package you pick for performance will suffer

Holley makes vacuum and mechanical secondary carbs - so they sell both. I see less about "taste" around sizing and configuration - this is driven by the application. "Taste" in brands is definitely true

Definitely agree that happiness on a street carb is all about intake velocity.

[67chevemall]

Well the truck is cleaned up and the 1406 is on there. I am getting new plugs cap rotor and oil/filter gas on pay day. Go from there.
The oil is draining now and the F cell is yelling for fuel.
Start it and see if I need the shop or not.

[BurnoutNova]

Originally Posted by Billla

A bit OT - but yes, there is!

The original ZR-1 was a special purpose 1970 LT-1 Corvette that required mandatory options that were typically only available with the L-88/ZL-1; HD brakes (J50/56), HD suspension, HD transmission (M-22) and radio delete. It could not be ordered with power windows, power steering, A/C, rear window defrosters or wheel covers.

A ZR-2 with an LS-7 454 was planned but never released.

very interesting, ive never heard of that! an LS7 corvette would have been absoulutely INSANE... if it could keep from breaking the axles, assumming it could catch traction also

i think thats kinda neat, they use rpo codes from the past on newer stuff, like the original LT-1 and LSX engine codes