Rebuilding my 351M as a stock 400. Planning to keep all the fuel system parts from the old motor. It has the standard Motorcraft 2bbl carb, with #57 jets installed (assume original). The EGR has been disconnected, and will likely stay that way. Has anyone got suggestions on where to go with the jet size? I've been told to enrich the mixture when the EGR is not in use, but how much?

Bob A
'77 F-150 4x4 "the project"

 

How much is the good question; I'm also researching this one. Would love to hear from a knowleagable BTDT.

I just dropped a new all-stock 400 in the hole left by a 351M in my 79 Bronco; seems to me that, even though I'm still running the EGR, the 2BBL Motorcraft is way under jetted. I'm hoping a local dealer might locate a set of jets for me to play with - don't know if any such pack exists though.

So bigger seems to be the right direction, and I'll post again once I hit carb nirvana (hope it's out there!).

Good luck Bob.

Jeff

>Rebuilding my 351M as a stock
>400. Planning to keep
>all the fuel system parts
>from the old motor.
>It has the standard Motorcraft
>2bbl carb, with #57 jets
>installed (assume original). The
>EGR has been disconnected, and
>will likely stay that way.
> Has anyone got suggestions
>on where to go with
>the jet size? I've
>been told to enrich the
>mixture when the EGR is
>not in use, but how
>much?
>
>Bob A
>'77 F-150 4x4 "the project"

 

Hello fella's, i've done the jetting thing not too long ago ( I'm not no A.S.E. certified mechanic or nutin ) and i couldnt make my stock 400 with the Motorcraft 2150 2v carb. To run much better. I rebuilt my carb. after three years of use because of a bump in the idle. One main jet was #51 and the other was #54. I checked every parts store there is, and no one could tell me what size jets were stock. I had a old parts carb. and took the jets out, they were #49. I put them in and run it, adjusted the carb. and did'nt notice any difference, i have a set of numbered drill bits, and started drilling from #48 to around #40 and started noticing no difference in the air fuel mixtures, i could screw them all the way in and there was no change in the idle. I drilled the #54 too a #51 to match the other one, installed the #51's, adjusted the best i could and thats the way i left them, with a bump still in the idle. If any one of ya'll could figure out which jet size works best, will you please post it? I hope ya'll have better luck with this jetting thing than i did, lots of patience does help. Please keep us posted. Rob

 

Well, Your just not gonna find jets at the Ford house or any parts dealer.
I called around to all to wrecking yards around town. Only one had any Fords as old as this. So went for a visit with a phillips and flat screwdriver in one pocket and a rag in the other. I spent about a hour under the hoods of every Ford/Lincoln/Merc in the yard old enough to have have a carb. I also dug around in a couple of piles of various carbs. You get the picture I'm sure.

I got lucky and walked out with two sets of different jets to try in my '79 Chero. Cost me 10 bucks and my truck runs much better now.

Good luck.

 

This may sound like a basic question:

Does a bigger number mean bigger jets? From the last post it seemed like he was drilling out from a 54 to a 51? Isn't a 51 smaller than a 54?

Jeff

 

>This may sound like a basic
>question:
>
>Does a bigger number mean bigger
>jets? From the last
>post it seemed like he
>was drilling out from a
>54 to a 51?
>Isn't a 51 smaller than
>a 54?
>
>Jeff


No, the smaller the number, the bigger the size.