Got a good deal on a brand new Holley 4260C 600 CFM Vac 2nd carb for my trucks engine to replace the stock Autolite 4300 weeping carb there. I am looking for what jets to start off with. According to the box, it's a Ford carb for a 200 to 400 CI motor. I am going to the dual stage power valve but my engine is a mid 70's with no work done that I know of. Stock intake, exhaust manifold but duals, points ignition (got a Petronix waiting to go in) with a C6 in a 67 F-250 chassis. Any information on this would be helpful.

 

I dont recall the factory cfm on that 4300 for a 460 but it may not be a bad idea to try and run the holley right out of the box just set the mix and idle as u would after a regular carb rebuild, you may be surprised! if not what i usually do in the case of swapping carbs is pull one of the primary jets from your original carb and see what size it is by the numbers on it. i know the older ford and holley numbers were generally pretty close in size. this should get you ballparked

 

No doubt the holley will be better than a weeping carb, the 600 cfm is sort of the lowest one wants to run on the 460's. I'd check your 4300 and see if it's a D revision which is the 715 cfm carb. I know some don't care for the 4300's but it might be worth getting it rebuilt or trading both for a higher cfm carb.

 

agreed with dustyroad on lowest cfm being 600 for a 460. holley.com has a cool carb selector that figures your cfm requirements for your engine based on the mods you select....being truthful on the mods helps you alot...bigger aint always better. or you can use the formula of VE x cubic inch x max expected rpm divided by 3456 = cfm VE stands for volumetric efficiency which with a stock engine is usually 75-80%

 

Using the carb cfm calculator on summitracing.com @5000rpms, the 460 needs 565cfm. The 600 should be fine on a stock motor. I am using an Edelbrock 600 on mine and it runs just fine.

 

Well, took the Motorcraft apart and it's the 600 CFM D0VF C carb. Primary jets are 65 set up but I have made a change and went with the Edelbrock Performer intake as all the EGR parts are leaking like no tomorrow. Plate is hosed and manifold lines are cracked. I did get the carb ready to mount on it and looking forward to this weekend finishing the top end. So now it's Holley 600 with 2 stage power valve and brown diaphragm spring, 68 jets right now, 1" 4 hole spacer but thinking of opening the bottom a bit, performer intake with new water neck and thermostat, pertronix ignition with pertronix coil, and all the rest. Going to be fun getting this dialed in.

 

I am curious what kind of mileage you are getting with your Eddie. I am about to swap my Autolite for an Edelbrock 1406 600CFM Square Bore mount. It belonged to a friend of mine who had it installed on a 383 Dodge engine in a Super Bee for about 2 weeks. The 600CFM wasn't even close to what his super stock 383 needed. But I am sure that Super Bee was putting out more power than this 460 Ford on stock form.

I am also running a C-6 automatic with 3.54 rear end gears. I am turning about 2,200 RPM at about 60 MPH going down the highway. Since my fuel gauge sender is malfunctioning and this Autolite is leaking from the throttle shaft and at just about every gasket it's difficult to get an accurate reading on present fuel mileage. Suffice to say, my old truck, a 1986 Ford Super Cab sporting a 460 with a 4-speed, 4.10 Sterling rear end, and a Holley 650 double pumper was getting about 12 to 14 mpg depending on how you drove it. If you stayed below 3,000 RPM, it stayed about 12 or 13 mpg. But you were only running 55 MPH. If you put your foot down to 70 MPH, the secondaries opened and the gas gauge moved faster than the tach!

So I am figuring my leaky Autolite carb may be the culprit.

 

All the ford 460s that had holley carbs on them were a 600 vac. sec. and the ones I have tore down had a 63 jet in the primaries. That is probably not too bad for a sea level carb, but I have ran my 750s all the way down to 68s up here, and my TA 670 down to 62s I believe, I bet a 600 would need high 50s up here. I also run leaner PVs in mine, 45 is the richest PV I have ever ran. I have ran a lot of 25 and 35 pvs too. The dual stage? Not familiar with that, but have to look into it. My 545 almost needs like a 35 on flat ground, a 65 for up hill cruising, and don't care for sled pulling. She leans out a little bit if you point it at a hill and try to stay out of the secondaries.

 

I am guessing 9-10. Never really figured it out. Make sure you get the kickdown kit if you have an auto tranny.

 

I will have to check and see what's in a stock Edelbrock 1406.

 

That's the #1483 Throttle Lever kit and the #1495 Throttle Plate kit. I have them both. I only need to pick up some throttle ***** to connect the throttle cable. I also have Jeg's version of the #8135 Fuel Line kit. It's about $10 cheaper than Edelbrock's kit. I could have probably fabbed up my own for even less, but Jeg's has done all the homework, so what the heck?

I just need to pickup a new EGR Plate gasket tomorrow and get it done.

I also picked up a Mr. Gasket 14 inch Air Cleaner that should fit. The OEM unit sits too low.

 

Check your plugs after driving it a while, they will tell you if you are a tad rich or not. I usually ran 66 down to 64 in the 600's I had on my 460. The 460 will burn about as much gas as you want to run thru it and love every drop too. But it doesn't always need that much either.. Good luck, that's a good carb for your motor

 

Just finished up the carb swap. I ended up changing all the usual gaskets - EGR mounting plate, carb insulator (the thick gasket) - and so forth.

The Mr. Gasket air cleaner I bought that was supposed to fit - didn't! The OEM air cleaner that wasn't supposed to fit - does! Go figure!

I also installed the fuel filter kit and removed a vacuum source plug and replaced it with a pipe plug. It seemed like a better way to handle a source of vacuum leaks than just capping off.

Afterward, I used some Gunk Engine Cleaner and gave the engine a bath. Now I can track down the oil leaks. The valve covers (big surprise) are a definite source of one.

I am hoping that it's ONLY the oil pan gasket and not a rear main seal leaking also.

Remarkably, the timing cover does not leak! (Go figure!)

This done, the engine runs even smoother than before! It always had a funny little hiccup to it. The kind of a hiccup that was irritating, but no real big problem. I suspected a vacuum leak or a throttle shaft (Ala Autolite carb), or some such thing.

Now it idles as smooth as a baby's butt and starts without even touching the accelerator!

Next project: Valve cover gaskets.

(Saving up to do BOTH fuel tank sending unit assemblies AND fuel selector valve with a connector! Then I get to put that wiring schematic to work! Found the sending units at LMC.)

 

just struck a deal on a 1979 f150 4x2 with a factory 460 it has leaky valvecovers and already has headers and a holley on it! i sense some tire smoking shenanigans and bench racing