I recently took possession of a '39 H my Great Grandfather bought brand new. I have been around this tractor my entire life. In talking to a guy I will be buying some parts for a general going threw. I mentioned my tractor has a dipstick. He tells me H's never had dipsticks and it has to have a 300 or 350 engine. I never knew of an engine swap, but anything is possible I guess. In checking engine numbers, it is the original engine, casting date 11-8-39. The dip stick passes threw the block. What I'm wondering is what is the true story here? The tractor was a demonstrater before Roy bought it so my guess was a dipstick was an option being showcased on the demonstrater. Since the H's had the check peckcocks, my guess is nobody bought the dipstick option. If my guess is wrong, please correct me because if this is a rare little option, I'd like my facts straight in talking about the tractor.