I have a question on this swap. I have a 75 Ford F100 SuperCab *360 engine with two barrel* . in no way am i wanting to do a certain speed at under ten seconds but was just curious if I would get better fuel economy with this swap and have more throttle going up hills with it also. TIA

By the way changing out the power steering gear box is one heck of a job I cant belive it finally went out after twenty five years only thing next is the tranny.. *crosses fingers*

 

I think you would see a difference with the carb and manifold and splitting the exhaust into duals. You have a borderline year so I would check to see if you are supposed to have a convertor or not, but if not, you will see a nice difference. I don't think headers are worth the trouble unless there is something wrong with your manifolds. It doesn't have to be loud either, just some nice turbo mufflers or even stock type.

 

I was thinking about changing from a two barrel to a four barrel but I am considering a Holley 2300 two barrel carb. It is a 500 cfm carb and will bold right onto your existing manifold. You might consider this option.

Does anyone else have an opinion on the Holley 2300?

 

I second the holley 2bbl( wish i never sold it ) i went to
a 4 bbl holley on my 78 351m and hate it..I am going back
to a autolite 2100 for now..the truck just seem to run better
with a 2 bbl then the 4. go figure...Now as for the 390 in my 69
it loves a 4 bbl!!!Something about the FE's????
joe
69 crewcab 4x4 390
78 supercab 4x4 351m (needs a 460)!

 

wl,
The holley 2300 500 cfm carb is the best 302 application i have ever used. the throttle response is always crisp and the bottom end is perfect. It will starve at the top end, but you've gotto push it hard.
I put some spacers in and got the top end i wanted. i actually put a 2 to 4 barrel adapter upside down and then put another one and created a "tumbler". It reduced my bottom end and gave me a significant top end increase. Anyways, it's a great carb.
My Way is the Highway.
KingFisher

 

When I bought my 79 F350 4x4, it already had a Holley 500CFM 2BBL carb on it. The previous owner rebuilt it and installed it on the 400 engine. When I push the pedal to 3/4, it goes like a raped gorilla!

 

My thinking my be wrong, but I think the 2BBL is more responsive and torquey on take off because of the increased air velocity that you have with the smaller carb.

The bigger carb will be better at the top end where you have more cfm, but it's less responsive. I remember back in high school, a guy had a Mustang with a 351 Cleveland and a factory 2bbl carb that would literally burn the tires off. Heck, I saw some big ol' LTD's do it too.

I also like the fact that you can tune the 2300 to your liking. I could never tune the factory 2bbl after installing dual exhausts. It was always too lean and the idle was never quite right.

You probably won't be able to tow your boat to the lake at 120 mph with the 2300, but you will certainly have no problems pulling it back up that steep boat ramp.

 

The front of a 4 barrel carb is actually smaller than a two barrel.

 

I run Holley 600 4bbl/vacuum secondary carbs on my 460s, and have run one on a 390.
Great low end and midrange torque due to the small primaries, and they pull fine on top end, even when towing dead Ch*vys to salvage.
I find them used for 50 bucks, dip and Jiffy Kit them, and press on.

 

I have a '73 F100 with a 390, 4spd, 3.50 gears and dual exhaust. It had a stock 2 barrel on it when I got it. I put on a cast 4 barrel manifold and an Edelbrock 600cfm carb on (with 1" spacer to clear linkages), I am very pleased. The fuel mileage stayed the same 11-12 mpg, but the power increase is well worth it (to me). There is a big increase in power at take-off and passing on highway. I would never got back to my 2 barrel.

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Marty

 

I just spent like $700 on a edelbrock 600 and a performer manifold for my 360 in a 73 F250 4x4. There is still something wrong with the set up. I do have good take off torque once she is warmed up, and she gets better milage. But at speeds over about 35 or 40 it's almost like putting on the brakes if I stand on it. Bog big time! She will accelerate fine slowely, but no power. I can't figure out the problem, and even though I spent so much money, I'm just about ready to put the stock 2 barrel back on. But it sound like others have had good luck, so I'm just telling you this so you have heard both sides of the outcome. Good Luck

 

[updated:LAST EDITED ON 17-Mar-02 AT 10:28 PM (EST)]taliesin,
Don't give up on that 4 barrel! The edelbrock is an excellent carb, it is based on the carter AFB. You have a tuning problem, it can be solved. First you need to check for vacuum leaks. You can visually check for an unplugged vacuum port, then with the engine idleing, spray small bursts of carb cleaner around the intake manifold and the base of the carb. If the motor changes speed, you have found your leak. And try temporarily pinching off the pcv hose. You will also want to make sure the carb is getting enough fuel. Check the hoses, and lines for cracks or kinks. Tiny cracks between the tank and pump can suck air and starve the motor. You may need to do a fuel pressure check. YOu need a guage for that. Also, Look down in the carb with the engine off and pump the throttle. Watch to make sure both nozzles squirt fuel. Sometimes new carbs have some junk plugging up a jet or accelerator pump nozzel. Run the engine with the air cleaner off, rev it up a bit and put you hand over the carb to choke it off, the engine will start to die, take your hand off, let it get reving again and repete a couple times. This will often draw any debris out of the carb. Also check your initial timing with the vacuum advance hose disconected. Modified engines often like more initial timing. You may want to experiment with bumping the timing ahead of the stock setting, maybe 5 or 10 degrees. If you keep it there will need to limit the mecanical advance in the distributor if it runs good but pings at wide open throttle. Try hooking the vacuum advance up to ported vacuum, then manifold vacuum, see if it makes a difference. Good luck, Let me know how you come out.