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Mv446 carb questions


Farmer Ray
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I have a 1979 f1924 with an mv446 engine with a holly 4bbl carb.  Wanting to get more power out of it for pulling up hill under 52000lb gvw. Thinking of a swap to a edelbrock ps2 carb but what cfm should i go to.  Or are there other better options? I don't find any cfm specs for the holly that is on it. Thanks Farmer Ray

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5 hours ago, Farmer Ray said:

yes both

Just going to a non governed carb will help.  Going with mechanical secondaries will help.  Bigger might help, but probably not with that governed distributor.  I suggest seeing if you can find a non governed one for it.  You sure it's a governed distributor and not just vacuum advance? 

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Its not a "governed distributor.'" The vacuum lines go to a centrifugal piston valve in the dist. body, and it opens up at a certain RPM allowing vacuum to pull the throttle back, limiting engine RPM. Replacing the carb with a non-governed model will eliminate the governor completely with the original distributor still in use, with the vacuum lines discarded. BTW, those distributors are noted for making a "smoker" out of a perfectly good engine when a bit of wear allows oil to be sucked into the manifold past the distributor shaft.  A good reason to junk the governor setup in itself.

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So are you saying i need a different distributor?  Or just different carb?  What do i need to do to dump the air pump? Or smog pump as some call it? will that help to?  I am leaning towards an edelbrock 800cfm ps2??  manual choke.  I think they have one for about 375$ and i think it has manual secondaries.

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Also whats the best rpm that i should try to run , i have been trying to stay under 3000, but i slowly loose ground and have to shift to 2-2 instead of 2-3 then i can wind up again.  Then i just crawl up the hill 10mph till i get to the top before shifting up then its good and i can get a run at the next hill.  The first i have to drop down to 30mph or so to go around the corner just as i start the climb.  

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Distributor will work if it's not worn out. If the air pump has its own belt you can just take the belt off, It doesn't make a whole lot of difference anyway. Those engines can go up to 3800 RPM with no problem, I shifted mine at 4000 when heavily loaded. The power curve drops off after that.

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  • 6 months later...

I spotted a 1984 s2300 with a L10 cummins engine how hard or big of job would it be to swap my mv446 to the L10  this guy also has one with a big cam s2500 ih truck.  but  my local mechanic thinks its to big for my s1924.  He also thinks the L10 is to big ......he really doesnt want to do it. So finding someone to swap it at a reasonable cost is the kikker.  Any ideas  i do have a dog house spotted what else would i need.  If i have a doner truck and tranny 9speed how bad a job is it?  Would it bolt in? 

 

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If you can’t get the job done under 3000 rpm (I certainly wouldn’t wind it any tighter), more carburetor is not going to add a single hp during a hard, slow pull. It could actually make it worse. You only have X amount of horsepower, and at peak torque you simply cannot just arbitrarily dump more fuel down the motor and make it go up the hill faster. All that being said , that doesn’t mean you can’t move up to a BETTER carburetor, away from that hideous governor set-up. Keeping the same CFM with a modern carburetor and ignition, you might even GAIN a  mpg or two. More help to ditch the y-pipe and go dual exhaust if not already set up that way. If you don’t have air flow through the heads, more carb will accomplish nothing, simple as that.

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20 hours ago, Farmer Ray said:

how hard or big of job would it be to swap my mv446 to the L10 

The answer to this question is going to vary wildly from person to person. If you have a “repair” shop and all you do is change oil, you probably think it is pretty darn hard. If last winter you built your own corn head to use on your farm you probably don’t think it’s that difficult. I don’t think that this is the type of job that just your average parts changer could handle. It would require a very good mechanic to finish all the details and make this work like it should in my opinion. The right mechanics are out there, but few and far between in my experience. 

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