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I've recently acquired a 66 Fastback. It's a near complete Shelby Clone project car. The body is an all metal rebuild with the classic Wimbleton white and Guardsman blue paint job. (Oddly, the previous owner did not include the hood scoop as part of the rebuild plan.) It's beautiful, nonetheless, with GT-350 running board stripes, Cragars allround, and its inspired me to finish cloning the car into a Shelby. The electrical system and emergency brake need to be re-assembled prior to the car being roadworthy. The drive-train is a complete rebuild with a modified A Code 289 and four-speed manual tranny. The engine has a Le Mans flat tappet camshaft and hipo lifters, rockers and over-size pistons that function in 302 heads. The dual exhaust has a very throaty sound and I can't wait to take it on to remote highway for a good test drive. I want to replace the current intake, carb, oil pan and rad in favour of the original Shelby look. Ergo, here's my question: Is it worth my while to track down the Le Mans 715 CFM Holley carb? I've heard these carbs can be problematic on street machines and I know that they are pricey. Any advice is appreciated.
 

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Sounds like your doing it. The 715 man they hold there price I saw one on Craigslist used $700 WTF. Expensive. I like the word Tribute instead of clone sounds human like ?. Good luck. I am running a 600 dual feed.
 

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Well, finding one isn't a problem. Paying is.

Cobra LeMans carburetor

They run just fine, well, as well as any Holley. Having driven Holleys on my daily driver for 15 years, I've seen enough. But if you are installing an aluminum T pan, Cobra intake, and Tri-Ys, then you should probably use the LeMans.

As for the hood, at a minimum you should get the 'glass hood with steel frame, or have a steel scoop fitted to your steel hood. I'm not a fan of the LeMans stripes, almost all Shelbys have them now, but in reality few had them when new.

741893
 

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"over-size pistons that function in 302 heads". I don't know what that is and there are too many variations or combinations of pieces and parts to guess.

If you are really serious about building a reproduction of a GT 350, you will need to start with a hipo 289 engine which has parts that are specific to the hipo 289 that are not A code. Then there is a list of other stuff the Shelby team put on the GT 350 that wasn't on a Ford factory mustang also. It can become rather expensive and its money you would not get back out of the car if you decided to turn it over.

Otherwise, I would probably put a throttle body fuel injection kit on it, ditch the solid flat tappet cam and install a retrofit hydraulic roller kit in the engine. It will, start, run and be a happier driving experience if you plan on driving the car. The engine that is in there probably should have been built with a stroker kit also and aftermarket heads.
 

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+1 The 715 carb is very much at home on the street. I also agree that you should "ante up" for the steel frame glass hood. The better you make it the more value you will see out of it.

22GT
I agree with you on the lack LeMans stripes. My '66 - 6S477 does not have them despite also being a Hertz car. The side stripes are/were always blue as well. 18 were shipped this way to Hertz. Ten to San Francisco Airport and eight to LAX. All were automatics with no roof stripes ( originally). When i bought 6S477 in '74 , I added ( rattle can) LeMans stripes so it would match my other '66 6S240 which DID have them originally. I did this so I could "bait and switch" when doing illegal street racing in '74. After a year , I got rid of the stripes.
Randy
 
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All this before driving it?
Fake the carb, er I mean making a tribute carb will work . Any 4V Holley can have the blocks and bowls added to "look" just like the other:) If you find yourself running out of A/F @ 6500 rpm very often then worry about one closer to 715dfm.
 

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Imo a 715 cfm carburetor is way too big for mildly built 289. I had a 570 Holley Street Avenger on a mildly built 302 and it ran great. The 302 had a mild camshaft, aluminum Weiand Stealth intake, headers and so on. I think a 715 is going to be way too much carb for a street car and that you could run into some issues. There are literally thousands of carburetors out there to pick from and having a Shelby clone wouldn't make me want to spend the money on an original style carburetor, especially on an engine it's likely not meant for. If it was a true Shelby with the original motor? That would be a different story. People always over carb their cars thinking they're going to get better horsepower or performance out of them. I always look at what the experts say... since you're looking at a Holley carb, why not ask them? They have a carburetor selector page on their site where you enter the cubic inches for your particular engine, the redline, how modified it is and so on and then it will give you a bunch of different options to choose from. Even a highly modified engine, which they classify highly modified as having an "aggressive camshaft, performance intake manifold, headers, ignition upgrade, aluminum/ported iron cylinder heads and 11:1 or higher compression" they still don't even recommend a carburetor of that size. They highest they recommend even for a highly modified engine is only their 670 Holley Street Avenger. I'd stick with something in the 550-650 range at the most. Depending on whether you want vacuum or mechanical secondaries, and on a mildly built street car I don't think it's going to make much of a difference, I'd go with a 570 Holley Street Avenger, a 600 Holley Brawler carburetor or at the most maybe a 650 Holley Double Pumper. The SA has vacuum secondaries, the other two are mechanical but all of them have an electric choke.

 

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Hmmm… All the GT350 65-67 came with the LeMans carb. It may be big, but not obscene. The GT350 came with the C3OZ-6250-C 289HP camshaft. The OP has the C7FE-6250-A, which I would hardly call a mild cam, at advertised duration 318°/304°, lift .528/.528.

As for size, I ran a Ford 3-2V intake on the street for 15 years, and that setup totals 785 cfm. That was with the C3OZ-6250-C 289HP camshaft. Ran great, even got decent mileage.

741911
 

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+1 22GT is right, The Holley list 3259 and -1 were SPECIFICALLY designed for the Cobras / GT350s by Holley engineers in '64.. Calibration is all important here. When you use "fit all" carburetors you are running the risk of the calibration being OK or bad, I ran the over the counter "Ford" Holley dual four set up for years on my 4spd GT350. The mileage was usually 16-17 with 3.89 gears and was close to the mileage of the original 715/Cobra intake. The "modern fuels" have cost us at least two MPG from leaded gas due to the alcohol used in it now.
Carburetors are stupid. They will only flow what the engine "sucks in". If the engine will only pull in 500 cfm according to someone's formula , it will still only pull 500 cfm through a 1050 dominator or multiple carburetion or a 550,570,600 etc. What changes is the big carburetor "sees" to little signal at the booster and the air fuel mixture suffers resulting in poor performance. That of course is an extreme example but is FACT. Many guys use "small" carburetors because their calibration is "close" to what their particular use is. Unless you have "hands on" experience it is difficult to "generalize" based on simple CFM ratings. All carburetors are not alike despite having similar CFM ratings
Randy
 

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While it's definitely not a stock cam, I wouldn't call it extremely radical either, especially compared with the aftermarket cams that are available today. I'm not sure of the exact specs/parts that are used on Jim's engine but if he doesn't have aftermarket heads or considerable head work done, no headers and is using the stock intake... I'd stick with a smaller carb. Just my opinion of course.
 

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The LeMans cam is [email protected] .050 and while it is "antique" in design ( 1964 origin) it was designed for FOUR Webers , not a 600 Holley. Shelby had already run the 1850 carb on 289 Cobras but found that the engines made more power with a 427 carb ( list 2699) that was 715 cfm. Holley engineers "adjusted" the primary metering block and added the LeMans float bowls and wah lah the 3259 was born. I realize EVERY person has his own opinion and experience and am not saying the 3259 is the ONLY carburetor to use. LOTS of 289/302s run well on 550,600,650s. I'm simply saying the 3259 will work fine. Run what you like , it's your car AND money.. I'll wave as I drive by you, with my over carburetion. LOL
Randy
 
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@patrickstapler have you ever had your engine/car on the dyno to see what kind of power it's putting out? I remember you talking about it in another thread about mufflers and exhaust but was just curious.
 

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If you are stuck on getting a 715 lemans carb, Tony Branda has them for around $1200;

Reissue by Holley of the Le Mans carburetor, same as originally used on 1965, 1966 & 1967 Shelby GT350's. Fits all 289-302 engines with manual choke only. Center pivot float model. Includes gaskets and mounting hardware. Limited availability, price each.
Stampings on air horn are:
  • S2MS-9510-A
  • LIST 3259-1
 

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Just to chime in on the Carb controversy. The size of the Carb relative to the rest of the motor is a throttle response as a function of RPM discussion not a will-it-work discussion or will it pull good HP numbers on a dyno. The GTs were made to run like hell close to redline where a 715 at 6500-7000 RPM can feed the beast. However, if you are running on the street or autocross at modest RPMs, the mid range 2500-5500 is where you want the punch. Here a 715 is not running efficiently. The throttle plate air velocities are slower than optimal to a) maintain good atomization and b) quick transmit time for throttle imput.

My ~400 HP 351 came to me with a new Holly 750. I had a fairly new 650 from my old motor and tried them both. At wide-open-throttle e.g. floor it and stand on it to redline, I didn't really notice a remarkable difference since I chip my car to 6 grand. However on an autocross course, I found the 650 had much better throttle response. The previous owner was perfectly happy with a 750 and I probably would have been too had I not had the 650 on the shelf and autocrossed that motor regularly so I had a good feel for the difference.

I visualize it this way, the engine doesn't know you want power till the impulse from the butterfly valves hits spark. If the a/f mixture is moving faster, your input will be more immediate. Now if you add a matching cam, intake, heads and exhaust for the mid range, your golden. In other-words, having the right carb dumping into too large runners or a huge open plenum made to move big volumes at 7k, you have the same problem and that thought process goes all the way into the heads through the valve openings. THat's why you run dual planes for mid range, they keep the velocities up in the mid range vs a Victor JR which is a huge open plenum made for moving BIG volumes at high RPMS.

Drag racers typically run huge carbs with big open plenums, but lets think about what they are doing. Stage, Rev motor to staging RPM (which establishes a good starting a/f velocities), green light - floor it. Carb opens, motor hits high RPMS instantly and stays there. Good velocity established and stays high velocity till done. BTW, this is the same for a dyno run - most dyno runs do NOT measure throttle response!!! Autocross and street is on-off-on-hold-off-back on... - lots of throttle nuance. A car with good throttle response in the RPM ranges the car normally operates, "feels" faster no matter what the dyno says! I have lost an autocross by a hundredth of a second.Throttle response maters and second place = first loser...
 

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I would have a hard time paying that kind of money for something that is probably not going to make much difference in performance. Nobody's going to see it most of the time anyway.
 
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