I have a late 1972 early L and need a new carburetor. The car was lightly modified before I got, so I don't know some of the specs on it, except that the carb is currently a cheap Holley. What size was the original carb for the '72 Pantera? I thought of replacing it with a 650 or 750 CFM Holley, but I also want the car to run well and don't want to "over carb" the car for moderate use. Any suggestions on the size I should use, and any other comments? Thanks for the help.

QUESTION How do I tell what size carb I need?

ANSWER You take the engine cubic inch and multiply by the maximum RPM and divide by 3456. If you have an automatic transmission you will need a vacuum sec. carb, a standard transmission can use a Double Pumper carb.

351ci x 6000rpm / 3456 = 609.37cfm I would run a 650 or 700 Double Pumper carb. So I could upgrade the engine with out changing the carb.

The 4300D spread bore Autolite carb I've seen rated at 715 cfm & 750 cfm in Ford literature.

Day in and day out, from mild to wild, the 351C likes a 750 cfm Holley (equivalent to a 650 cfm BG Demon). As long as the carb is jetted properly, installing a 750 cfm Holley will not be over-carbureting the Cleveland.

Installing a 600 cfm Holley carb is definitely under-carbureting a Cleveland, it won't rev past 5000 rpm.

cowboy from hell

I run the 670cfm Holly Street Avenger, Ford iron open chamber heads with a little massaging, Ford roller rockers/pedestal mount and a mildly healthy cam. This combo works well for me, I can easily rev to 6200-6400 rpm.

Larry

I run a Holley 670 also .... jetted to 68 /72 and the car runs fine ... 750 ? maybe vac secondaries on a slighlty modifeid engine .. but thats too large for a small block.

Ron

I'm not being argumentative, I want to be a little more thorough and explain my recommendation.

The 351C 4V is not a Weezer (oops, I meant Windsor) and its not a SBC. Comparing the 351C to any other motor of the same displacement doesn't work, the same rules don't apply. The cylinder heads are that different. The best motor to compare a Clevo to is a 396 Rat motor.

The 4300D carb installed by Ford on the 351C was also used on 460 Fords; it is about a 750 CFM carby. It is a little bit bigger carby than the Rochester Quadrajet. Installing a Holley 780 on a Boss 351 netted a gain of only 10 BHP compared to the 4300D, and this was most likely due to the richer jetting of the Holley, not because it was a larger carburetor.

While the Boss 351 in the US had a 4300D carb, the Boss 351 in Australia had a 780 Holley borrowed from the Boss 302. Ford also sold a 780 Holley over the counter in the US for the 351C via their OHO parts program. The recommendation for the 351C has always been 750 CFM ever since its introduction. The guys with really hot Clevelands upped that to 850 Holleys.

The earliest "non-boss" 351C 4V motors (M code) had Autolite 4300A carbs, rated at 630 cfm, they were definitely under-carbed, and struggled to rev to 6 grand. The earliest 4 barrel Clevelands produced in Australia also used the 4300A carby. US Ford switched to the 4300D carb in late 1971. By the time the XC Falcon was under production (1976) Ford Australia had switched to a Carter Thermoquad rated at 750 CFM.

Hall Pantera sold a 600 Holley, along with the Edelbrock Performer intake, DeTomaso valve covers & Pantera air filter as an engine dress up package way back when, and as far as I can recollect Gary's was the only shop anywhere selling a 600 Holley for a 351C.

Outside the Pantera world, in the mainstream where Mustangs, Cougars, Torinos & Montegos roamed, the Ford performance shops all recommended 750 Holleys, and these were heavier vehicles, the majority of which had automatic transmissions.

Keep in mind, the 351C 4V likes headers with 1 7/8" or 2" primaries. 2" primaries on a Weezer or a SBC is an apostasy, but its de rigueur for a 351C 4V. Doesn't it make sense that a motor that likes a "bigger" exhaust system may like more intake capacity as well? This motor likes more of everything compared to those "other" motors of similar displacement. This was a serious high performance motor designed for mass production, those cast iron cylinder heads will support 750 BHP naturally aspirated. Do that with a set of weezer heads, or a SBC double bump head.

Anything under 650 CFM is definitely under-carbing a Cleveland. Sure you can get by with the 670 carbs, and one or two Pantera shops sell 700 CFM Holleys for the Pantera. Since a street motor spends most of its time at lower rpm the difference is not going to be noticeable. But the 750 Holley is not over-carbureting a 351C, not at all, it won't bite you, I guarantee it. The 351C really likes a dialed in 750. The same way a Clevo wakes up when you install a healthy cam, the Clevo wakes up with the 750 too, but can remain docile & drivable when the jetting is dialed in. Even Ford on two continents installed 750 carbs on their hydraulic lifter cammed Cleveland motors.

Long Live the Clevo

Cleveland Symphony Orchestra


cowboy from hell

I have installed a 750 double Pumper holley on a stock 351C. Changing jets, power valves, etc it ran OK and a little rich. Replace the 750 double Pumper holley with a 700 double Pumper holley again changing jets, power valves, etc and it ran much better and was not rich at all.

Now I have also used a 700 double Pumper holley on a 351C with a just a little larger cam. Again after changing jets, power valves, etc ran great. So if ran good with a 700 you put on a 750 well after all said and done the 700 was better.

Now same engine change heads and cam and end up with a 780cfm double Pumper. Ran great and the 700cfm was under carb.

Now take that poor oiling system thin wall 351C and use it as a Boat Anchor. Install a (What did George call it?) "Weezer" fuel Injected it and your done. The only thing better then the 351W would be a 5.4 supercharge mod engine..!

quote:

Now take that poor oiling system thin wall 351C and use it as a Boat Anchor.

BLASPHEMY!!!

quote:

Originally posted by LF - TP 2511:

quote:

Now take that poor oiling system thin wall 351C and use it as a Boat Anchor.

BLASPHEMY!!!

LOL..!

GEEEEZE George... I am glad you weren't being argumentative .....LOL!

Ed....