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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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#41 ·
Thanks will do, I replaced the needle and seats and all the carb seals, new accelerator pump diaphragms, but the power valves seemed to be ok so I reused them cause the rebuild kit came with much larger ones. Also my pump shot squirters were .28 and .31, not .21 and .22 ( they were hard to see until I removed them. The metering blocks looked like the ones I had in my old 4150 Dominator.

How do I measure the carb bowls, do I need a caliper? or will a ruler suffice?

Also from what Im getting from your post, the base timing will be higher than the WOT timing? So it will actually be retarding timing as you accelerate?
 
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#42 ·
Gotcha, as soon as we are back to normal here in NJ I will proceed to get gas and start her up and set the base timing, might be a few days cause gas is in high demand with al the power outages here from the hurricane..I will post the results when i do get her fired up..Oh and I picked up the Champion plugs you recommended.
 
#40 ·
Heres what i see. Go ahead and borrow an on head spring tester. Check em.If it is a solid roller,even 220 seat psi is ok on the street. Take the carb apart and soak it. Make sure all your bleeds are clean. I see it doesnt have screw in idle bleeds, so you can take a pin vise and a number bit and increase the idle bleeds a little,just check the existing size.Check the primary butterflies for position and make sure they aren't covering the idle wells i guess you call em, if they are you can drill the butterflies for more air so they can be closed down. Get the jetting down where its not washing the engine and a low power valve that is 3 or so in. below the idle vacuum so it wont be tipping in. Put a hot enough plug in it to keep the tips clean, like a - 6 ngk.tune the squirters after you get it idling and driving correctly. Make sure you have adjustment on your idle mixture screws, if you can close em down and it keeps running,its too rich idle mixture wise. Just basic get it running stuff. You can worry about cam timing and such until after you get it to respond. It will take a great ignition to keep it going. Lots of initial timing, but before it is hard to start and trys to detonate. Let the engine tell you want it wants, not the neighbors. The cam is a little large on .050 duration for the street and thats what makes em soggy on the bottom(no cylinder pressure at low rpms) That can be somewhat fixed by cam timing,but later on you will porb find out that a more up to date cam is in order
 
#44 ·
That's a distributor used for racing so the distributor itself contains no mechanical or vacuum advance capabilities. If you want an ignition "curve", you will need an ignition box that is programmable. It's not unusual for the timing to be set to the max power setting and then an ignition timing retard is used to crank it up.
 
#47 ·
Ok i read way more on this post then intended.. doesnt look like money is an issue.. dont be offended but the carb looks like junk. Call Willy's Carbs in the morning and they will hook you up with something nice.. the carb looks mismatched and i havent seen bowl bolts like that in a long time.. also every carb I have ever had on and engine like this had the primary throttle blades drilled..
 
#48 ·
Vinnie: You said that your 355 isn't stock. I had to use the vac. sec. 780 on a 425 hp 454 in NHRA Super Stock and we made 806 hp in Super Stock trim 20 years ago. I NEVER liked the non vacuum secondary on the street for streetability and every time I made the 780 so that the secondaries were manual, it always sounded better, but didn't run as fast. I suppose I might have made more power if I could have used an 800 or 850 cfm. Do they make one with vac. secondaries. My point is, you can make good horsepower with a vac. sec. smaller carb that is more streeable and doesn't foul plugs or hesitate. The car ran 9.40s 142mph at 3650 lbs, with a Turbo 400 20 years ago. The trick was to have the right size nozzles in the accelerator pump system and the correct stroke in that system (add the larger pump capacity) - and let the vac. secondaries come in relatively quickly, but not instantaneously.
 
#50 ·
no, I was noting that the op has what appears to be a race car with a race carb. We ran 2 wcfb s on an 11 second 265 powered 56,,,it too was a race car.The op does not have to use a vac carb and the rest of the car is race looking.
yes a 750 vac would work,so would a 750 carter

It just looks like you skipped over the original post,,,
 
#51 ·
Yeah. "Back in the day" we couldn't add the Rio pump in Stock or Super stock; but we got around that by stacking gaskets on the stock pump housing to increase the volume. Also used a Cadillac pump plunger and cut some off the end of the pump rod shaft to pull it all the way up to the top of the housing for the longest usable plunger stroke. We needed to do that because we didn't have a secondary pump. We also ran relatively lean jets like 75s (primary) and 76s (secondary). If you need mush more (like in the 80s), then your induction and exhaust are working together correctly. Stepped headers that were properly tuned with the intake, head ports, and cam, pulled more fuel and required that we use the smaller jets. I really can't remember what size the needle and seat was, but it was larger than stock, and about 6 to 6.5 psi fuel pressure at idle. Floats were set just slightly on the low side of the inspection windows of the float bowls with the larger seats and that much pressure. As per the original question of a streetable carb - start small (780 or 800) vacuum sec.; get it running good asnd then throw on that big carb and see if it is any better. Flat top piston (9to1 comp ratio) a good timing starting point is about 34 to 36 degrees total.
Large piston dome and compression in the 12 to 12.5 to 1 range should theoretically require more total timing 38 to 42. I guess this car is somewhere in between. I guess I'd start about 36 or 38 degrees total.
Just Sayin'
Dave
 
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#54 ·
Short of that, the locked timing is about as good as you will do. Is there a crank trigger on the front of the motor? What ignition box is on that car?
Yes crank trigger up front, and MSD 2AL.

Also from what Im getting from your post, the base timing will be higher than the WOT timing? So it will actually be retarding timing as you accelerate?

Some engines need this. ( Timing is basicly based on the cylinder pressure (high or lower) and relative engine load in any one driving mode. low CP and low engine load wants high timing....high CP high load WOT wants less relative timing.

cruising at part throttle with some rpm but light engine load...steady Hiway driving... wants high timing.
Idle , low load low CP + exhaust dilution ( cam overlap) needs high timing..

EG WOT the cylinder pressure is high. The fuel burns fast. ....... When idling the cylinder pressure is low (and with a 260deg cam there is a lot of exhaust reversion dilution, slows combustion requires a lot of timing to get the burn time right.

Exactly how yours will be best set up depends on what you have to work with there.
I was thinking of getting the MSD electronic distributer..Yay or nay?
 
#61 ·
Both items would need to go to a racer and he would take it apart to appraise the parts.sounds like a lot of race ready parts for a good home.The transmission is worth quite a bit.Price will depend on the racing seen in your area,,,craigslist will be a waste of time.

NOTE: when someone offers to tear the engine down for inspection,the buyer has to pay for the gaskets etc needed to reassemble.Make sure you get the money up front.
your replacement engine will be 9 ish and a TKO 5 spd is 2200 plus clutch etc
 
#64 ·
a small engine making (potentially) north of 670 horse power is something that you can feel.Its not for everyone because it takes a lot of work and maintenance. Drive it and you will be hooked.Take some time and learn about race engines/street engines,and figure out when a street engine becomes a race engine.Yours looks like a race engine that is streetable. It will be expensive to play with,you decide if its worth it??? I did the same thing,,,
 
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#70 ·
Actually I fired it up and checked the timing today, here is the weird thing...At idle (about 1000-1100rpms) the timing reads around 30-36 degrees, and when I rev it it stabilizes right to 34-35 degrees..It seems as if it is locked out cause i can not seem to retard it at idle..Ever see that before?

On s die not it seems like the carb is fairly well tuned so far, a little rich at idle you can smell it, but when you rev the engine in quick short stabs it revs right up with no hesitation or bog at all..

Any suggestion on the timing thing?
 
#75 ·
Agree with fbird. You built this and you dont know? or you bought it and figured what the hell.

It is nice and im sure it can be tuned to perform on the track. Open the hood and look at what you have. Do you think that will be a good cruising vehicle? 1100 rpm idle, nice. If your combo is correctly matched for that intake. It is a monster. The carb you have is a good match and probably needs some adjustment for good wide open power.

If you want a satisfing ride you might want to rethink some basics. Not that what you have cant work. The opposite can be true too.

My idea is to start stock and build up. A step at a time. You teach yourself how each peice effect the cruise and the performance aspect. Sell the old on ebay, when you advance. You will get to the ideal ride. Kind of novel, but my thing as been a mildish engine, and everything I wanted nitrous to be I found with supercharging.
 
#76 ·
I actually traded a car for this and think I got the better deal for sure. I have a decent idea of performance cars but learned mostly on fuel injected imports. This whole carb and distributor thing is new to me. However I did have a twin turbo Nissan 350Z that went in the 10s that I built and tuned.
I think I am just over complicating things when learning old technology..
 
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