[font size="1" color="#FF0000"]LAST EDITED ON 05-Mar-01 AT 06:38 AM (EST)[/font][p]what carb would be best to substitue on my 1985 302 5.0 2bbl AOD F150 instead of the original equipment MoToCraft Feedback 2bbl that I have now? I've hooked my DVM to the O2 sensor and since there is no mechanism that I know of to 'lean out' this carb the mixture appears way to 'rich' 1200mv on start up and 1000mv after warm up at 50 mph cruising on flat road in overdrive)and the tail pipe burns black. The basic PCV system remains in tact. This truck has had the cat,smog,PCM and most related vacume lines removed. It has the trottle valve control rod for the transmission and don't want to have to 'jury rig' these controls....It runs ok, but the gas mileage is in the pot. I'm going to install a Performance Distributor soon also.
I think I want to stay with a 2bbl and don't know much about Holley and other carbs that might work satisfactory....I'm not a hot rodder and just want it to run efficiently.

I would also like to replace the V belts with a serpentine belt. Does anyone know if this can be done and what'll take to do it. It has a mechanical fuel pump and is stock now....thanks!!

 

You might find an older car/truck with the original
2bbl without all the elctronics (they all will have some smog)
but it might not have the kickdown setup for the trans. If you want to pull all the smog/electronics off and make it run right, you will have to go aftermarket. This means 4bbl manifold and small non-emission carb with ford kickdown option installed. Some people like Holleys, some people like Edelbrocks.

 

I would also recommend getting a 2bbl off of an older vehicle without feedback setup. The 2 bbl Holley carbs have different bore sizes and spacing and a different bolt pattern than the Ford carbs. If you get a 4 bbl carb, get one from an 83-85 Mustang GT or 84-87 351W HO from a truck or van. This carb has factory style attachments for accelerator and kickdown and also has electric choke.

In response to your other question, yes you can switch to a serpentine setup but you need to change your timing cover, water pump, and fan to a reverse rotation setup. The only timing cover that has both the reverse water pump and fuel pump provision was on the 83-85 Mustang 5.0, otherwise you can switch to an electric fuel pump.

1979 F150 Custom: 75 351W, Edelbrock & Holley
1987 F150 XLT Lariat: 88 351W EFI
Chevy 454: waiting for a truck (Mazda?Nissan?)

 

Whats' a motorcraft feedback carb? Is this like the electronic Q-jet, and precursor to Throttle body injection? I have a 79 f-150 w/ stock type motorcraft 2v carb. I've had lean problems for awhile. I've upgraded ignition and recurved distributor. After passing the state emmissions I took the slip to my local speed shop, which pointed out that it was apperently jetted very lean. They sent me to a carb specialist shop for re jetting because I guess motorcraft jets aren't readily availible anymore. It's just been rejetted to be in a more ideal fuel/air mixture but still legal. Replaceing the jets is pretty simple in my motorcraft 2v aside from knowing what size to use and finding the size you need. The carb shop also diagnosed that I need a new EGR valve that mine is opening too early or fast and creating a lean condition. Anyway, as far as rejetting, it's a matter of unscrewing a pair of jets from the bottom of the fuel bowl and replacing w/ a different size. Have you considered trying Holleys 2v pro-jection throttle body injection conversion?
I've heard that they work well from a couple of ppl. I know the TBI in my Chev Camaro is very trouble-free and much simpler than port injection should I need to replace something on it. I believe the Holley projection system is essentially the same idea although there is a fair amount of installation involved esp in modifying the fuel delivery. As far as 4v carbs, I bought a 600cfm Edelbrock for another 302 I used to have and then put it on a 390 I have, it works pretty well and has lots of parts support for it. Certainly Holley types also have tons of parts available and ppl that know alot about making them work well. I've heard that improper TV cable adjustment will take out your tranny so be cautious there.

BBT

 

BigBrownTruck's situation highlights the problems with original
emissons carbs. An original carb is calibrated for all the smog
stuff operational. If you de-commission all the smog equipment
you should go with a very early 2bbl carb or aftermarket. One
thing that will rear it's head is pinging at light throttle on
the highway if you disconnect the egr with the emissions carbs.

 

I have a mechanic friend, who believe's in Holley 750's. Doesn't matter what you are going to do, he thinks the 750 is the carb. Personally, I don't neccesarily agree with him. I have both a 600 edelbrock and the 85 stock HO carb. The only thing would be careful of is the HO carb. These carbs had some problems after being run for a while. Something with metering blocks, if I remmember correctly. If I were you, I would install a dual-palne intake and a four barrel carb. The edelbrock improved the mileage over the HO carb when I installed it. The mileage had dropped over the years of driving with the HO. The overall performance was pretty much the same eccept at the upper end. The performer intake can be picked up for reasonable money, I've even seen those on ebay. Otherwise, rejetting the carb may be the way to go.
Good Luck,
Rich

 

[font size="1" color="#FF0000"]LAST EDITED ON 10-Mar-01 AT 07:22 AM (EST)[/font][p][font size="1" color="#FF0000"]LAST EDITED ON 10-Mar-01 AT 07:06 AM (EST)[/font]

:-> THANKS TONS EVERYONE! You guys are the Best!!
I just installed a new Holley from Summitt and threw away the FoMOCo feedback. I still have to adjust the kickdown rod or get a cable control rig for the trans but the big carb hassles seem to be licked now! When I took off the EGR mount/spacer from the intake it revealed yet another small intake leak due to a partially blown gasket where EGR crud was continually sucked pasing thru the adapter plate into the intake.

Anyways,....I expect my DUI distrib and 'livewires' any day now from Perf. Distributor and I'll let you know how that goes.

If I get it all running right I'm wanting to buy and install a PowerTrax rear-end in my open 8.8 / 3:55 now. Anyone have any installation hints or other things I should know about that mod?

Also, how much power/and/or gas mileage would dual exhaust REALLY gain over my single exhaust with crossover pipe???

Thanks again,
Jan :-)

 

If legalities aren't a problem, putting a small 4bbl and duals
on a motor makes it "all that it can be" and will be an all
around good power maker and still be stock internally. I believe
this is a good starting point for somebody just starting out
modifying their vehicle to suit their purposes.

 

Hi,
I now have a new Holley 500 2bbl...works great, but I had one hell of a time installing a kickdown cable kit...it works great too now though....

what about these thermactor pipes?

This pipe connects the heads in the rear of the engine and come up to some kind of a valve. A previous owner has removed whatever this hooked to and I'm tempted to remove the pipes completely and 'plug' the holes in the head.
Will this harm my engine?
The Midas shop said 'it's a dealer part' and they couldn't fix it.
If I don't have to have I don't want it...
I'm rebuilding the old truck back to the basics....because the original equipment had conked out. i.e., the Fomoco 2bbl, the old distrib
It runs good now, but noise due to this tube leaking that connects the heads described above.

Thanks!!!
Jan2
Clarence

 

This piping went to the smog pump. If you don't have a smog pump there is no use having the piping on there either.

 

Big Brown Truck....

Do you remember what jetting your carb had before they rejetted it? and what they rejetted to?

 

Jan2

Is your carb perhaps a high altitude carb? Feedback solenoid sticking out of the back of it.