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Hello everybody.
Surfing through Craigslist today, I stumbled across this: >FORD 351W Parts! Holley Carb, Heads, and Intake<
I want to swap my 351 in my F250 over to a carb so I can open up a few more options for cam and other power upgrades. There isn't anything wrong with my EFI, but I think it will just be easier for me in the long run monetarily.
I only need the carb and the intake to do the swap, but do you guys think this is a good price? I was thinking about offering him 100 bucks for the intake and carb and seeing what happens, but I wanted to see what you guys think first.
I also know that I still need a Fuel Pressure Regulator and Throttle Cable to swap it over. Does anybody know what length throttle cable I would need?
Thank you in advance.
if that is the stock holley that was on the 80's 351w(and it looks like it from what I remember from several years ago),run far and fast!! I swapped one of those engines into my 78 and no one could ever get the thing tuned right,ended up buying a new holley truck avenger,adjusted it myself,and it made the 351w run GREAT.
I would swap to MAF, but I don't have the cash for all that conversion stuff. I don't think the carb will be that big of an issue with the colder climate.
Besides the carb and intake you also need an ignition, distributor, and a bypass fuel pressure regulator, and once you buy and install all that you'll find your motor is no more powerful than it was with EFI. If you were to instead take that money and upgrade the cam and exhaust on the motor as it stands right now you'll be far ahead of where you are now in terms of performance and the truck will still start normally when it's 20 below in the winter.
I just bought a set of long tube headers and 3" exhaust for it that will get put on as soon as the salt is gone from the roads. I also planned to put in a bigger cam than the SD system will support once I put the carb on. I already have an ignition also. Ill be getting a fuel pressure regulator. Why do I need a distributor?
The available EFI friendy cams will allow the motor to produce all the power it's capable of producing so that bigger carb cam isn't going to do any better and may actually produce worse results, but it's your truck so you get to do what you want with it.
Originally Posted by GNR22
I already have an ignition also. Why do I need a distributor?
Is the ignition you have is designed to work with a TFI distributor?
It might be my truck, but I like the advice you guys give, you know what I mean? The ignition module is an MSD...I want to say 6al, not sure though. And if it COULD produce worse results, that's definitely not the route I want to go.
I've looked over a lot of the SD friendly cams, and they just dont seem aggressive enough for what they cost. What exactly happens if you put in a bigger cam than the system should support? I know you lose vacuum, but what else happens?
Like I said, I haven't really made up my mind on what I want to do with it right now. But I want to be able to take the truck on trails, take it mudding, and still be able to pull trailers and such. I already have a set of 4.11 gears that I will also be putting in to replace the 3.55 gears also.
The available aftermarket EFI cams aren't that agressive in the big scheme of things but they are significantly bigger than what Ford installed and that's what matters. You didn't mention what cams you were looking at but your motor is a flat tappet so most cam and lifter sets are only $150-$200... no matter the grind. The old SD EFI system relies on a steady vacuum signal to determine engine load and it typically loses all control if you install a cam with a weak or unsteady idle vacuum.. which means the motor will run but it won't idle worth a damn and it'll stall on you a lot. Cams that produce a lumpy(unstable) idle typically have long durations that make power at high rpms, but the stock heads on a 351 become restrictive at about 4500rpm so these cams often make quite a bit less low rpm TQ and even less peak HP than a cam with a more suitable powerband. So like most guys that are just getting into this you have a decision to make, do you want a motor that sounds all bad assed but doesn't have enough grunt spin a tire, or one that idles like stock but will throw rooster tails on command?
I would prefer to have one that is a good reliable motor, so one that idles good would probably be a good idea in this case. I was looking at the Crane 44232 and the Comp 35-255-5. I liked the numbers from the Crane cam over the Comp. But I suppose you are right, it is a lot bigger than the factory ford cam. Do I need to get new valve springs and retainers? My motor only has 90k on it and runs fine as it is right now.
What size tires are you running GNR22? i honestly think you should consider doing the gear swap first and formost. You might find that you dont need a cam at this stage. Exhaust upgrades are always a good idea though so proceed there.
gearing will make more difference then a cam ever will on the motor you have currently. if you find you need more then do the cam but gears, gears, gears.
right now I have stock size tires. I know what it's like with 4.11 gears, that's what it started out with. I put in 3.55 gears to compensate for the lack of OD. but i do so much city driving that it isn't worth having 3.55s any more.
On paper the Crane 444232 it's pretty tame looking but in DesktopDyno it produces surprisingly good numbers and in real life it just works fantastic. If you want to maximize the potential with the stock heads just add 1.7 rockers, that will put valve lift up near 1/2" which will give you 95% of what they can do. No need for new valve springs with this cam.. the matching springs are pretty close to the stockers and they can handle 1/2" lift as well. I'd also agree about the exhaust and longtubes will produce the best power gains on a truck.
Ok then this sounds much better than getting a carb and gaining nothing with that investment. Thanks for setting me on a better track. Any idea what 1.7 rockers cost roughly?