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What is a good street carb?

36K views 174 replies 17 participants last post by  Dajerseyrat 
#1 ·
What street carb would you recommend for a fairly angry 383 Stroker with a 600 lift cam and about 11:1 compression? Currently it has a racing carb on it that is about 850cfm with mechanical secondaries. In this set up it like to load up and foul out plugs at idle or part cruising. Im looking to tame the car down a bit for the street, not a daily driver but a weekend warrior. Im looking for something I can install and drive out of the box with the minor adjustments..

Recommendations and why?
 
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#8 ·
You do not need a new carb and you cannot buy a magic carb that will run perfect out of the box.
You need to dial in the one you got ..The problem is more if a ignition set up problem than the
carb.

What cam?

Distributor
Timing curve, timing at idle
carb model number pri jets sec jets power valve.
Fill in the blanks.
Can show you how to set it all up to run clean, not load up and not foul plugs.

Its a matter of set up details not a i need a new carb problem.
The car is not too big.
Well I just got the car and had it ideling for a while and the previous owner told me it likes to foul out plugs. The car was set up as a full road race car.I cant recall all the detailed specifics and havent taken the carb apart to see the jetting.
Carb: Dillman Racing Carb
plugs: NGK V power 7 R5671A-7
Ignition: MSD 6AL
Coil:MSD Blaster 2
Cam: Lunati #50199LUN
I have the reciepts for the engine and spoke to the engine builder. Was told it was a 383 punched out to a 389 and about 11.0:1 compression
Rear gears are :308's
Tranny is a Jerico 4 speed

Does this help?
 
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#12 ·
it looks like you have a race car bolted to your race carb and race engine.what are you trying to accomplish? are you racing it? curious how you like the jerico? I considered it but with out a speedo I went with a street friendly tko.
that carb is obviously a holley thats been modified
 
#14 ·
Im looking to tame the car down so I can take the car to local cruise nights and not have to change the plugs after driving there.I havent gotten the car out on the road yet, just picked it up and having fouling issues, plus the massive hurricane that were getting hit with up here has put a damper on my day.
 
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#25 ·
Start by getting new spark plugs Champion RC12YC gap at .035"
Will do.

carb jetting.... timing at idle, manifold vacuum at idle,,, idl speed (rpm)
Timing at max advance...
carb power valve rating. Is it blown? reduce the fuel pressure to 6psi at idle.
Jets 70 Front 74 Rear
Powervalve 3.5 F/R
Pump shot 21 Front/22Rear

Once I get it to actually start and stay ideling I will tell you the rest.



the old plugs are for racing. Too cold for street use. idling etc. (use the champion RC12yc)
Ok thanks was wondering which plugs to use.
Carb venturii diameter (not the boosters) carb throttle bores diameter.
jetting. brand name of the metering blocks power valve vac rating.?
This is a little beyond my understanding,how do I measure these?
If this motor has a solid roller cam its a good idea to reset the valve lash.
I assume it is.
 
#16 ·
From what I can read your cam is very close to what I have in my engine. It will be expensive to drive on the street,no doubt.Not sure what intake that is? dart?My engine makes peak power at 6500 rpm,yours will likely make peak at 7500 rpm.
your intake and carb likely work best from 3500 up,so launching the car will be a pain.Hope your 1st geat is lower.I bet that carb flows over 1,000 cfm.
I think you will need about 22 degrees initial timing and all in by 2500.about 35 degrees total.It should idle at 950 to 1000 rpm.no idea about jetting because the carb will flow more than the 850 it started with.
You will at some time need to book some time on a "mustang" chasis dyno( or another dyno that can load the engine and powertrain) dont bother with an inertia dyno.
you will need a few booster venturis,jets,air bleeds etc when you tune it. other than 0 to 15 mph it should drive fine.If you road race it then its fine. Gearing will be sugguested to you by someone and this time I will probably agree. I went to 3.50 gears but I also have o/drive so I didnt lose anything. use a speed calculator and 2500 rpm as a cruise rpm for that engine.
hard to drive race cars on the street
 
#20 ·
You can cruise a Fuel Funny Car if you're willing to put up with its idosyncrasies. As far as a blower motor, the blower will tame down a radical cam and make the car driveable on the street. It appears to me that you have ignored the advice of one of the sharpest tuners on this board, F-BIRD'88. Back up and re-group.
 
#22 ·
hpete,Im not going on a rant,just read what tech posted above and really reconsider why anyone would ever put that intake on this engine? look at the cam and carb and the big intake.scroll back and look at the headers,look under the hood at zero street stuff,jerico trans,,, etc
 
#23 ·
He wants to drive it on the street and his question was about idle quality. As I see it the problems he has are caused by crosstalk between the cylinder banks during overlap (+60 degrees if I'm reading the cam card right). A duel plane intake would eliminate that, I think that a plenum divider in the single would accomplish the same thing but I have no way to be sure. The op's carb is big enough that the dual plane shouldn't lose much up top. I prefaced my remarks with "if it was mine" being mindful of my own budget I zeroed in on what I thought was the most cost effective solution.
 
#24 ·
Guys,

Im not concerned with making top end HP on this motor, I might take it to the track once and a blue moon, but my plans for it is just a radical weekend warrior. I thank you all for your advice and I guess there is no simple answer many different opinions on what is the best combo. I have in the past read many people who have the opinion that a vacuum secondary carb is better on the street, which is why I started this thread.

I understand the basic principal of the correct timing and tuning the carb I was just wondering if i decided to go with a quote on quote "Street" carb on this motor would be of any benefit? Or can I get that carb that is on there to cruise at 3-50 mph nicely to local cruise nights?

Im opting for hotter plugs and I just took apart the carb for inspection cause I suspected contamination and boy was it dirty inside. I forgot that the guy hadnt run the car in a long time and the fuel probably left all sort of deposits..My plan now is to clean out all the fuel lines and carb and replace any parts in the carb that are suspect. Right off the back I got a sticky Needle and seat and tons of grime in the bowls.

The carb has
70 front jets
74 rear
3.5 powervalves
21 pump shot nozzles in front
22 in back







 
#26 ·
you have what looks like a 650 plus horse power engine with the parts I see.It will not be tamed easily.The only thing that would make it a lot easier to drive would be something like big stuff fuel injection,computer controlled crank fired ignition and a really steep first gear or automatic with a nice soft converter. A road race car does not like automatics as much as a stick
 
#27 ·
The previous owner did say he thinks it is a 600hp engine:thumbup: Which I am not opposed to driving around on the street if I can get it dialed in. The car was all dialed in so I can only assume my issue is plugs and a dirty carb and bad fuel at this point.

I was wondering if I sell this entire motor and tranny combo what I could get for it. Oh and it has a complete dry sump oil set up.
 
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#32 ·
Yes it say for about 8 months..I added about a gallon of fuel but didnt check to see if there was old fuel in it. when I started to try and run it, I smelled the race gas that was in there, so it had fuel in it. Im going to clean out all the lines and carb first. I have an adjustable timing light I purchased after the last fiasco. (which by the way turned out I was 1 tooth off on my timing after replacing the dizzy but the carb was still defective and poorly machined.)

This car sat just as he put it away and had about 40 hours of track time on it in the past 3 years. It was set up for road racing and has seen track time at Limerock and Poccono raceways. The previous owner said he had it up to 160:thumbup:. I will post more pictures, it is set up to go..

I spoke with the guy that built the motor and he said it is closer to a 389 cause the block was checked and was extra thick so they went .40 over. However the owner said he thought it was closer to a 421 based on his calculations with the head chambers..I dont know what heads are on there, they say "pontiac" on them and look aluminum..

The dizzy on there is a MSD pro stock one and has no vacuum advance that I see, also the timing should be set correctly for the engine by the previous owner, so Im assuming just setting the base timing over would suffice to get it up and running.





 
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