dual fuel H

Did all 1939, 1940 Farmall H"s come out with the dual fuel manifold and hole in hood for the other tank?? Just noticed that the old H I got stored in my barn that was my grandpa"s has the hole in hood and dual fuel manifold and rad. shutters. I knew it had the shutters but it has been years since I"ve used the tractor and I was younger and didnt know that much about dual fuel tractors to realize it had the hole and manifold.
Did IH just stamp all hoods with the hole or was this at one time actually dual fuel.
Were the carbs the same for gas engines and dual fuels??
One other question, years ago the dip stick for the hydro system fell down in the hole. Just the metal rod went down, would I be able to fish it out with a magnet you think? Whats at the bottom of the filler neck? just part of the res.?
Thanks
Ryan

I think it was an option since I have 4 1940 Hs and none of them have the extra hole in the hood or the tank

I do not know of any gas only 39 to early 41 farmalls. Could be, but they would be rare. The carbs were different, but the Distillate carb will adjust to gasoline well.
Fishing out the stick is possible, but with the time it has had to settle in it might not come out. Leaving it is OK.
Braze the new one to the washer!
Refill the reservoir with 6 gal. and mark the full line. Jim

The majority of those early Hs are of the distillate or kerosene burning variety, but the gasoline only option did exist. If you look at the underneath side of an H hood WITHOUT the hole, you will find where the hood has been pre- stamped right where that hole should be, sort of like a knock-out plug. Not all H hoods may be that way, but I have seen several that are.

If the tractor serial # is 20891 or higher a standard H tractor should have a X1 after the tractor and engine serial #, if it came as a gasoline. With the way parts are swaped around on some old tractors it may be hard to say how it came if below the above serial #. If there's parts other than gasoline that you know to be original to tractor, it was equiped for another fuel.
H serial 602 gasoline was tested at Nebraska in 1939. Gas heads are shown in 1940 parts books, don't have a 39 parts book to know about it.
Gas hoods don't have the starting tank hole.
Dad and uncle had a 41 gas H on the farm that I spent many a long day on at planting time. Serial # 6xxxx X1.

There is no X1 after the serial #.

Ryan,
The filler neck is just a pipe nipple threaded into the top of the housing. Taking it out would make fishing easier. If you give up and make another, the full mark is exactly 9-1/2" below the bottom of the washer. The end of the rod is 11-3/8" below the bottom of the washer. Send email if you wish to see a couple of pictures taken of the one I fished out of my '51 H.

My '39 is a very early one (four digit serial number) and it is gasoline only. It does not have an X in the serial number.

Can't answer the question about the early options, but I can say that the distillate option was still a strong one in 1939. The F-20 and F-30 and tractors with similar engines continued to be made distillate-only right up to the end, if I have my info right. One thing I can say: I was "active" on IHC tractors from the age of about 8 (1939) until just a few years ago, and in all the years I was around IHC tractors with kerosene/distillate engines (low-compression, hot manifold), I never saw ANYBODY go to the trouble to use kerosene or distillate.
It is a royal pain in the you-know-what. To start, you had to make sure the carb was clear of kerosene by opening the drain, unless you were sure you killed the engine the night before by shutting off all fuel, or shutting off while running on gas; open gas valve; start; warm up good and hot--steam from radiator, or proper indication on temperature gauge available on some tractors; work and keep hot--they didn't work well on light loads and slow engine speeds--you could expect some sputtering; shut off kerosene, turn on gasoline if you preferred to stop with the carb full). Incidentally, those petcocks along the side of the crankcase were meant to be drained down to the lower one every morning if you had used the tractor for any length of time the day before--kerosene or distillate would condense enough to dilute the motor oil--another nuisance to add to the mix.
I guess it's obvious that the low-compression ratio necessary for kerosene or distillate didn't get the most power from gasoline, which can take quite a bit more compression before
detonating. There were lots of aftermarket kits
available for raising the compression on the older tractors, often, I believe, in the form of pistons shaped to increase the compression ratio. IHC, in fact, sold "5000 ft." and "8000 ft." pistons, which were intended for use at those altitudes where the air is thinner. Still, I imagine those pistons were sometimes used for increased power at lower altitudes. I often wonder if they might have given a higher compression ratio than would have been good for the bearings. Anybody out there have experience with such pistons? What were the results in power and in reliability of the engine?