I should start out with a disclaimer: in all the years I have been around old 2-cylinder tractors, basically since I could stand on the platform of a 60 and see over the hood, I have never actually restored one. I have taken several out of the backs of barns or out of hedgerows, but I have never done much more to them than what was needed to get them back to work in the field save for a rattle-can paint job. Because of this, I have always placed useability ahead of authenticity. I like to think that most of my modifications are both reasonably tasteful, and in the best spirit of what Deere engineers from the 1940's would have done with access to some of our modern technologies: 12volt electrics, electronic ignition, etc.
THE SHORT VERSION:
With the correct John Deere muffler, my M finally sounds good and runs better too! Instead of the generic muffler's hollow pa-pap pa-pap, it makes a deeper, more solid wa-wop wa-wop. And instead of the straight-pipe's lack of low-rpm grunt, now I can get into road gear from a standstill using only about 1/3 throttle. I am really amazed at the difference in performance between the generic muffler and the authentic JD part. Also, not to bash Stanley Mufflers too badly, but the JD part is of much higher build quality.
THE LONG VERSION:
When I got my M, it had a muffler off of a Chrysler minivan. Being young, married, but so far lacking in the offspring department, I saw this as a bad omen and quickly replaced the minivan muffler with a cheap, generic, Stanley brand tractor muffler. It sounded much better than the van muffler, but the generic muffler never sounded quite right either. I wish I had made a video to show you all what I meant, but the best I can describe is that the tone was wrong and it sounded cheap and hollow. A few years later I tried a chrome stack which sounded fantastic, but I also noticed that I lost a lot of the famous two-cylinder torque due to a lack of exhaust back pressure. The lack of torque meant that raking hay uphill was problematic. On flat ground I could rake in 3rd gear at a fast idle, but going uphill caused me to have to downshift and run in second gear at nearly full throttle... Which means more fuel burned per hour, almost to the point where my massive Model G could have done the same job for the same fuel cost.
Last week a friend of mine took me over to see his grandfather. The grandfather's old shop turned out to be the local John Deere dealer he ran back before the days of the mega-franchise dealer network. The dealership opened in the early thirties and had originally been the old man's father's, but he started working there about the time the 20 Series were introduced in the late '50's. The parts room, showroom, shop, and office look like a time capsule straight out of the 1980's; typewriters instead of computers, posters of 'the new 55-series tractors' on the walls, and shelves full of manuals and parts diagrams. Bit-by-bit they are selling off the dealership's remaining stock on eBay to pay for my friend's grandparent's medical bills. Some people have a stock portfolio, this old guy had his tractor parts. Anyway, my friend took me back to the parts room where he dug up a new-in-box M series muffler. Not a replica but a brand new, never before sold to the public, still wrapped in oil paper, muffler. The old man was really happy to meet someone my age (30-ish) who is still using an old Deere as a tractor and not as a show queen, so he charged me what the muffler was listed for in his early-1980's suggested dealer price book.
I'm going to stick to my 12volts and electronic ignition system upgrades, but I was wondering if anyone else has had a similar experience with OEM vs generic parts? What else could I be missing out on?