Is a 600 cfm double pumper holley with mech secondaries too much for a 12a streetport?? Anybody with experience in this dept???? Thanks for the help in advance guys!

 

Yeah, I'd say that's overkill. Maybe for a bridgeport, but maybe not even then...

I think you already know what my advice is...

 

i'm running a 600 single on a street port with a holley pump and fpr with out any problems!

 

sterling...

 

If you tune it right you should be fine with that. You don't need anything that big for a streetport 12A but if you are getting a deal on the carb, I'd go for it.

 

Ran one on a stockport 12a once...

 

600 single feed on streetported '74 13b.

 

Well my 465 runs outta juice REAL quick and is having gumy problems..... a buddy of mine is will to sell his 600 real cheap to me and he's pretty much a pro at the holley carbs. BTW Racing beat says in theor catalog I have that they use a 650 on their bridgeports and a 600 on a street 13b. So how much bigger can a 13b be compared to a 12a really?? .1 liter? And from some of the guys on here I could at least try since they've had success! As long as it's tuned.
And I don't think I'm going the sterling route cause I already have a 465 holley and if anything I'll just rebuild that. I just have been wanting a bit more fuel.

 

check your fuel filter. rebuld that one before you buy a bigger one. have your holley friend tune yours. i would still go with a sterling, however youve already made up your mind and im not gonna beat a dead horse

 

600 cfm is much more than enough for a streetport 12a. You can get a 800 to rune on a street port 12a, but I wouldn't recomend anything more than a 600.

 

i'm running a holly 600 on a stock 12a not sure the jet # tho
when the time is right , (money time same dif)
bridgeport her i'd get the 600 there is room for improvement.

 

just because you can do something doesnt mean you should. just because there is room for improvement with the 600 doesnt mean that he wants a bridgeport, which is harder to be streetable. and not to mention putting a carburetor on an engine its too big for hurts your power. it will hurt flow velocity and thus your efficiency making the throttle response lower, and drastically effecting your over all power, your power curve and gas mileage.

 

While driving the car it definately feels under carbed. I didn't check the plugs like i hoped, I'll try again in the morning........ if they're white thats gotta be my problem. Undercarbing is hurting the engine just as much as over carbing I imagine. Doesn't sound good........

 

i just cant imagine a 465 wouldnt be enough for a streetport.


For argument's sake, we could also take the theoretical needs of the 12a @ 10,000 RPM at a VE of 100%, which comes out to 405 cfm

http://www.sterlingmetalworks.com/air_delivery.htm

 

Hmmmm, thats something to think about....... What about the octane? I know when it comes to stock NA you want the lowest octane possible basically and as soon as you turbo you need the higher octane. So when you go street port do you need higher octane? Cause I've been running the lower stuff just like I always did with the other car.

 

Well I checked the plugs and they were what looked to me to be PERFECT. They were a nice brown but not burt or too light. So today we took it over to my buddy who's a wizz with holleys. He imediatly retuned the "float bowl screw" which was off by two whole turns and now it's much better! It won't stall anymore but still sounds like it's starving a tiny bit on the top end......... so heres what I'm pretty sure's wrong now, The intake is ok to use on a stock or street port but my carb was set up for a stock and this is a street...... they may need the same CFM from racing beat but they are tuned WAY differently depending on the ports. So I think I might need some bigger jets......... whatcha guys think???

 

Bigger secondary jets, but since yours is a vac secondary you will need the QFT metering plate upgrade to be able to re-jet. What spring are you running in the diaphram? I tune with a wideband, after rejetting efforts and changing power valves I have my 670 avenger dialed in just great.

 

i would say rejet, but i cant help you. i dont know jack about tuning holleys. maybe your friend can help. and +1 for using a wideband to tune if you can afford it, and make sure you keep a log of what you did to the carb and what effects it had on it. otherwise it will be like your herding cats.

 

you said the plugs look perfect so leave the jetting right where it is.
you need to check the fuel press on the top end under full load to verify proper press
try plumbing a gauge using braided ss fuel line taped to the windsheild so you can see it while driving and check the plug color immediately after full power run don't let the engine cruise/idle that will show you the mixture at full throttle

 

thats some old school tuning, i havent heard anything like that in a while.

however if you know what your doing it works, to an extent. its not the most accurate/precise, but for the budget most of us are on, it will do the job.

 

Well I know the carb isn't tuned right for the engine considering the whole stick port on a street thing....... I think I'm just gonna get a 465 CFM holley already set up for a street port, anyone reading this thread got one?
This way i can keep the stock setup for the stock spare engine I got in case this one blows...

 

im not gonna lie, that seems like a very inefficient way to to get your car tuned, you can just write down what jets you have now. get it tuned, then if this motor blows you can just switch the jets back out. thats why carbs have jets so they can be versatile, and not only applicable to specific applications.

 

But by the time I get new metering plates, jet kit and labor for my buddy helping me I could have already bought another carb and have a spare now........ But I haven't made my decision yet..... I'll ask him what he thinks.
Does anyoe know what jets racing beat put in their stock port 12a carbs and what they put in the street port 12a carbs? Maybe that way i could just buy the jets I need.

 

Jetting is not that simple. Put that carb on a 12a at sealevel and then put the same carb on one at 1500 ft and it'll be completely different. You need to tune to your needs and area. A wideband and a little schooling and you'll be tuning it yourself in no time!

 

i ran holley 465cfm on my streetport 12a.
do you have an aftermarket fuel pump? mine ran like crap when i had the stock pump in there, ran a lot better when i put in a holley red fuel pump and changed out my fuel filter. id recommend getting a wideband in there so you can see how much you are leaning out in the top end. might just need to adjust the secondaries or re-jet.
if you get a 600cfm it will be a way different tune. my s/c 12a needed a 600cfm to flow correctly dont think you'll want that size for an N/A streetport 12a.