LP manifold

1468 Chris · Sep 12, 2011

I have a farmall 400 that has a very badly cracked manifold. Im wanting to put a 450 manifold on it but can not find one. I found today brand new (reproduction) LP manifolds for 400 and 450. Can i put a LP manifold on my gas 400 and not have any problems? I know that the LP manifolds "flow" alot more than a gas manifold.
Thanks

big jt · Sep 12, 2011

The Flow that LP manifolds get is from the fact that there is no heatsink between the exhaust and intake side.

Cold air is more dense just like putting a small turbo on.

If you aren't gonna work the 400 hard it should work ok. If you are gonna work it hard you will have problems with the manifold Iceing. This is caused by the heat needed to vaporize the liquid gasoline, that's why gas manifolds have the heat sink.

hth

jt

Anonymous-0 · Sep 12, 2011

You can switch the manifolds with no problems. The dimensions of the LP and gas manifolds are the same as far as exhaust hole in the hood and carb location.

rhtx55 · Sep 12, 2011

You can purchase "aftermarket" gas manifolds from this site here,Ebay, Steiner's, Farmall parts.com & many others.
If you want a used original manifold in good shape, I would advertise on this site, or contact Bates Corp in Bourbon Indiana, a local Farmall salvage yard, Ebay, or your local Craig's list.

sflem849 · Sep 12, 2011

(quoted from post at 17:10:54 09/12/11) You can purchase "aftermarket" gas manifolds from this site here,Ebay, Steiner's, Farmall parts.com & many others.
If you want a used original manifold in good shape, I would advertise on this site, or contact Bates Corp in Bourbon Indiana, a local Farmall salvage yard, Ebay, or your local Craig's list.

What he said and the gas ones are going to be cheaper to boot. That is because the lp manifolds are made to cater to the tractor pullers (who love to spend money)

CenTex Farmall · Sep 13, 2011

I wouldn't put an LP manifold on a regular use gasoline tractor. You need a little heat for complete fuel vaporization, especially with the ethanol contaminating today's fuel.

Just last week I put a factory LP manifold on a 450 LP that had been equipped with an aftermarket replacement gasoline manifold. I happened to do some measuring and the diameter of the intake and exhaust runners was identical.

The LP manifold is not going to "flow" more air than it's gasoline counterpart. The air will just be a little cooler, that's all. Then you may have to fatten the mixture a bit to offset the poorer atomization and fuel economy will suffer.

1468 Chris · Sep 13, 2011

Ok thanks. You pretty well just made my mind up for me. I will be using the tractor as it has a mounted 234 picker and i'll be doing some pulling with it also. Thanks

CenTex Farmall · Sep 13, 2011

No problem.

The stock class guys win all the time at the local pulls using the regular manifolds.

Now if you were replacing, say, a hot manifold from a distillate or kerosene tractor then there would be a significant improvement. However, you almost never run across those anymore.

LP manifold

1468 Chris

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rhtx55

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sflem849

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CenTex Farmall

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1468 Chris

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