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My front left fender has 4 embossed hole location markings on them. Two large rings aft, two smaller rings forward, that are toe'd in looking forward forming a trapezoid. Are these the marks to mount the blower assembly - which according to the manual takes 5 holes? The dimensions do not measure according the locations in the manual either. My son guesses siren location?

Those hole locations in the fender might be for the gas fired heater, because they dont work for the hot water type. Nothing else was ever mounted there.

I'll have to go with gwalker's guess. All the M37s I ever saw with sirens in the Air Force had them mounted on the right fender. The heater, if installed, was always on the left fender.

Makes sense that the gas fired goes over these markings - not the hot water version I have. Oh well, I'll have to spot in the fender and drill! Thanks for confirmation.

Both the gas and the hot water versions mount on the left front fender. I have a TM 9-2855-45 that came with the heater kit I have but not installed, which is the manual on how to install a hot water on a G741 series truck that has a drawing of mount hole locations on the fender as well as locations for the hoses thru the side panel and cab hot air and power cable ducts. If you need copy of the page with mounting hole locations let me know, but a correct M37 heater should fit the mount knockouts on your fender but if it's not an orig M37 heater, well that's another story.

Carter - hey thanks! I bought my fender heater kit from John Bizal at MW and have the manual with the desired hole locations. We looked at the embossed rings/knockouts on the left fender and they do not align. All the locations, center to center, etc. in the manual don't match the marks.

B-T-W, I lived in Fredrick, MD!

knattrass wrote:Carter - hey thanks! I bought my fender heater kit from John Bizal at MW and have the manual with the desired hole locations. We looked at the embossed rings/knockouts on the left fender and they do not align. All the locations, center to center, etc. in the manual don't match the marks.

B-T-W, I lived in Fredrick, MD!

I took a look at mine and like yours it won't line up with the knockouts. I put a gas fired Southwind on my last M and that did work with marked fender holes so you are correct that to use these water heaters holes have to be drilled and that's what has kept me from installing the kit all along, I don't like the idea of punching big holes in the cowl and drilling holes in the fender. It's just that now that the cab is welded up and repaired I hate adding holes , but heat is nice. Carter

Consider before drilling, These heaters work well except for the blower motors generally leak & fill up with rain water. You'll have to fabricate a cover for the motor to eliminate that problem. I don't like them for a couple of reasons, #1 I agree with Carter, don't like punching holes, #2 it's very frustrating to work over that dinosaur sitting on the fender every time you need to access something under the hood on the left side. #3 you can no longer easily remove the fender to hood filler panel for easier access into the engine compartment because the coolant holes pass through it. From a mechanics point of view, it's a real hindrence. If you are a collector that wants a perfectly original vehicle, go for it. If you are after a daily driver or similar use, don't install it, you will come to hate yourself in the morning. Better options for heat exist.

"don't install it, you will come to hate yourself in the morning. Better options for heat exist. "

I doubt I will ever install it, along with my dislike of adding holes I also don't like the defroster duct location and have hit my knuckles on them more than a fiew times.

No doubt the defog panel looks like a high school welding accidents - sharp edges, corners, yikes. But a puriest has got to follow the foot steps of the manual.... I actually have my original Red Dot solution put back in the box because we bought the heater from MWM.

I too need a heater for my M37, I recently purchased an original fender mount but have not yet installed it. After reading all the responses to KNATTRASS'S heater posting I am confused.

Would like folks to weigh in on the best route to go for a heater. I am not a purist just want something that is practical

I was looking to install heat and at the time, no M37 heaters existed. I looked into mutt's but did not like losing all the foot room, plus the issue of finding defroster ducting. I put alot of effort into looking for a solution for something around 25K BTU. I found a CatPower cab heater by Red Dot. Its 30K, twin 24v fans, small size 16x5x3 1/2. It fit between the glovebox & center vent support with 4 bolts. The l-brackets that came with it were perfect and it barely showed below the dash. We bought two 24v push/pull marine switches to allow left, right, or both fans. We bought 2 threaded shutoffs, 4 90 degree elbows, and 5/8 heater hose. We had it all installed and the only thing left was to figure out a dryer vent type of temp defogging vent. Then Bizal offered M37 heaters - everything came out and is in the box. I'll probably try to sell the Red Dot when the dust settles.

I'm going with a Mutt heater because they are so readily available (and I already won one on E-Bay). I have not yet installed it but have seen pictures of one mounted under the dash, and also a different mount under the passenger seat. I'm not sure I like the idea of the miles of hose and ducting to go the seat route. Removing the inner glove box might allow me to tuck it up farther under the dash. BTW, I just found a new 1970's era universal in-line manual heater valve that will work perfectly with the heater cable. They make them in 5/8 and 3/4 sizes. Slowly but surely I'm piecing it together.
Gary