Let me explain some things so you all understand whats going on. When I built the 383 for my 76 camaro it was built as a race motor. In the mean time I got one heck of a deal on a tubbed and full race ready 75 vega so I dropped a sweet 355 in it and put the 76 camaro on the street. Well I had a bad accident in the vega and that pretty much put an end to my racing days. Now I am stuck with a bad ass camaro with a nasty 383 on the street.

I had a holley 750 double pumper on the 383 for a while but it was choking off the engine so bad that it would start to break up above 5,000 rpm. A friend of mine (hard core racer and mechanic) handed me a 1050 and adaptor to try out. Well right away I picked up .3 untuned. Once it was tuned I gained almost a half a second in the 1/4 and was able to wind her out to 7,000 at the snap of a finger so I went out and bought my own progressive linkage 1050 and dialed it in and sold my 750. Well for the last couple years I have been trying to drive it on the street and the 1050 is simply to much for the street but its awsome at the track. No matter how I tune it, it simply fouls plugs all the time from sitting at lights and idleing alot. The 1050 just is not a good street carb.

I am finally sick and tired of it being pig rich and fouling plugs on the street and am in need of a new carb and am coming to you guys for advice.

Here is my combo

383 stroker with 13.5:1 compression (yes I run a 50/50 mix of race fuel and premium)
Ported Brodix track 1 heads milled down to 61cc
Port matched Victor jr intake felpro 1206 gasket if memory serves me
6" crowler rods
4340 forged callies crank
Crane saturday night special solid cam http://store.summitracing.com/partdetail.asp?part=CRN%2D110981&autoview=sku

Cam Style: Mechanical flat tappet
Basic Operating RPM Range: 4,000-7,000
Intake Duration at 050 inch Lift: 252
Exhaust Duration at 050 inch Lift: 260
Duration at 050 inch Lift: 252 int./260 exh.
Advertised Intake Duration: 288
Advertised Exhaust Duration: 296
Advertised Duration: 288 int./296 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.536 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.554 in.
Valve Lift with Factory Rocker Arm Ratio: 0.536 int./0.554 exh. lift
Lobe Separation (degrees): 106



I am thinking about a holley street avenger 870. According the holleys site this is what they choose for what I am looking to do. What do you guys think? I am open to any suggestions or thoughts. It is going to be 100% street driven. I will keep the 1050 in case I ever get the bug to race again but its been 7 years now since the accident.


EDIT: Here is a video of my car idleing in park. It idles at 1,500 and drops to 900 to 1,000 in gear. http://video.google.com/videoplay?docid=-5438345282970814499&q=1976+camaro&total=11&start=0&num=100&so=0&type=search&plindex=3

Didn't you leave me some smart a** coment about the 1050 and the 383.

Didn't you leave me some smart a** coment about the 1050 and the 383.


:rolleyes: Like I said its great at the track on my 383 but a dominator has never and will never be a good street carb. Not only does it run great on my 383 but it worked perfect on the 14:1 compression .650 lift solid roller 355 I had in the vega.


http://img.photobucket.com/albums/v426/prostreetcamaro/P1000350.jpg

If it's 110% street then the 870 vac secondary carb will do. If you want to drop a little bit of more coin into a carb and get it right the first time call up Pro Systems. He can even turn your Dominator into a nice street carb from what I hear.

ProStreet I was just kidding.

The 870 Holley will be a nice street carb but my suggestion would be something with a better fuel curve for your engine. I would run a Holley 830 annular especially considering the high compression you have. The 830 is an excellent street double pumper due primarily to the annular boosters, yet it's designed for race applications. I run one myself after seeing how well it worked on a friend's 11.5:1 street roller 383 in a '72 Camaro RS. This car runs bottom 11s full-weight and all steel with a Goodmark steel cowl hood, so it's no fly weight. The 830 annular is almost as good street manners-wise as a smaller 750 because of the annular boosters, yet is capable of supporting a lot of HP, so it's close to the best of both worlds.

ProStreet I was just kidding.


ahhh you got me! I guess I came across wrong in the other thread and you got me in this one so we are even! :cool:


And to Smokin and Dirt those are very good suggestions and I will look into them later today!

Well here is an update guys. From my understanding Patrick at prosystems builds awsome carbs and is highly respected. I decided I might just get him to build me a nice 4150. Well after talking to him he said my 1050 is fine for my engine combination and that he can make it streetable AND gain 15 to 30hp on top of it. Sounds like a win win situation. What do you guys think?



Hi Patrick,

We have an excellent rebuild/update program for your
Dominator.

The XC program includes our Red CNC Billet double
step boosters, our adjustable air bleed configuration
(that actually responds to tuning), non-stick gaskets,
drag float, jet extensions, live-tested, wet-flowed
with a complete wet-flow portfolio that shows all of
the hi to low jetting parameters, for easy jet
selection (if any is needed we're usually dead-on or
within 2 jet sizes).

We disassemble the unit completely back down to the
raw castings and simply start over and build it to a
combination suited for your application. So we can
make it quite streetable. : )

I have a copy of your techsheet so simply box it up
and send it in. Most programs are in the $390-450
range but its actually tough to hit $450.00

Typically I see 15-30 more hp out of this program
for most dominators in your horsepower range and if
the need arises you can spray it up to a 400 shot (you
never know) : )

With a good fuel curve and improved booster
atomization and improved driveability its more
consistent in operation from day to day and also much
easier to read your spark plugs.

We are currently on a 8 day turnaround. Just box it
up and send it in.

Glad to be your builder Patrick.



Patrick James
www.prosystemsracing.com
727-490-5717

Sounds like your going to have a hell of a carb if you go through with it.

Let me ask about some of the basics'. With that cam im sure your vacume is very low while in gear, so have you compensated for that with your power valve? I like the idea of the annual booster carb also. I was really surprised that you could not get the 750 to work, there must have been some other issues to that particular carb to have made it do so poorly.

Let me ask about some of the basics'. With that cam im sure your vacume is very low while in gear, so have you compensated for that with your power valve? I like the idea of the annual booster carb also. I was really surprised that you could not get the 750 to work, there must have been some other issues to that particular carb to have made it do so poorly.


The 750 worked amazing up till 5,500 rpm then the engine would start to break up. No matter how it was jetted or tuned it simply wouldnt flow enough air to allow my 383 to breath. It got worse when we put the better flowing Brodix heads on it. As soon as I tried the 1050 the problem was solved and I was able to bring the engine up into the power band and gained quite a bit at the track. Im not going to claim to know alot about carbs but my friend thats been racing for years and owns a performance shop does and he is the one that built my 750 and went to the track and tuned it for me. He said it wasnt flowing enough air and thats why it starts to break up in the upper rpms.

Patrick dose awsome work! Our camaro did daily driver duty for a long time, even with a 780 DP he built. Top notch work! You wont be dissapointed if he dose your carb.

Isnt there some sort of online cfm calculator that tells you how big of a carb to get based on intake, rpms, and some other stuff?

Isnt there some sort of online cfm calculator that tells you how big of a carb to get based on intake, rpms, and some other stuff?


Yeah and according to it it says my motor should take an 870. I trust Patrick at prosystems when he says my 1050 will work good for my engine combo.

Unless you MEASURED either the airflow or connected a vacuum gauge to a manifold pressure port you really don't know if "airflow" caused the breakup.

My opinion, after doing lots of dyno work over the years, it wasn't an "airflow" issue related to the capcity of flow of the carb.

I have broke in quite large engines on the dyno with 750 Holley carbs and made break in pulls with airflow measurements approaching 850 CFM. This supported well over 600 corrected HP. Does that cause a power loss? Yes, given the 6" of manifold vacuum under those conditions. Does it make the engine "break up"? no

Every "restricted class" race motor we test has to run with a carburator that is WAY too small, hence the term restricted. None of these break up due to the carb venturi being "too small".

Just thought I'd clarify that for you as I think there is another issue with the carb.

I agree with Patrick as the Avenger would not be my first choice for that type of motor, either have him dial in a Dominator or a Holley HP series carb.

Should I go with a 600 or 750 cfm performer carb for my 350? Im doing a mild street build

Where did this come from??

"Didn't you leave me some smart a** coment about the 1050 and the 383."

Didn't the old 375hp/396's rect port BB's came stock w/ the old tried and true 3310-1 Holley 780 vacuum secondary carb on it so go from there and as always, imho here..

pdq67

Yeah. Its says I need like a 600-650 cfm depending on rpm's
Ive heard that carbs are underrated by 10% so a 600 is really a 660 or something. Is this correct?