Idea Exchange - 1940s and 1950s Engines

I'm currently working on engines and designs for my company, and figured that I'd go and do things in a more or less chronological order, starting back in 1940 and progressing through time, adding landmark designs every once in a while, then various iterations in between to help fill in these gaps.
I've noticed around here that just about everyone has been making engines with all of the fancy modern technology. not being much of a car buff myself to be honest, or even mechanically minded, I'm not really all that skilled with most of the engineering (my first attempt at a V8, mostly for fun, came out at an underwhelming - I think - 89 HP when I tried to copy a Fiat aeroplane engine from the late teens and early twenties that got nearly double or triple that historically).
Since then I seriously downgraded, and have been toying around with making analog designs from the late 30s and early 40s to get a sense of what works.
For those wondering about my engine, here it is:

For those wondering about the GA1937 393cc, the engine is designed to essentially be an American version of what's in the Citroën 2CV, for GA's Citizen line which is inspired by the Volkswagen, as well as the 2CV itself. Small, underpowered, but cheap and rather reliable, designed for little more than simply getting people on the road.
I can probably make a few changes to the engine I'm sure to cut down on emissions, though from what I've read with how broken the emissions calculations are, it may be best to largely ignore that line.
Comments, critiques, criticisms, perhaps anyone else building engines that have their own pieces from a similar era (of any size, design, or purpose)? I'd love to see what others are doing at the early end of the industry since most are using only the latest and greatest tech in their showcases here it seems.
I've noticed around here that just about everyone has been making engines with all of the fancy modern technology. not being much of a car buff myself to be honest, or even mechanically minded, I'm not really all that skilled with most of the engineering (my first attempt at a V8, mostly for fun, came out at an underwhelming - I think - 89 HP when I tried to copy a Fiat aeroplane engine from the late teens and early twenties that got nearly double or triple that historically).
Since then I seriously downgraded, and have been toying around with making analog designs from the late 30s and early 40s to get a sense of what works.
For those wondering about my engine, here it is:

For those wondering about the GA1937 393cc, the engine is designed to essentially be an American version of what's in the Citroën 2CV, for GA's Citizen line which is inspired by the Volkswagen, as well as the 2CV itself. Small, underpowered, but cheap and rather reliable, designed for little more than simply getting people on the road.
I can probably make a few changes to the engine I'm sure to cut down on emissions, though from what I've read with how broken the emissions calculations are, it may be best to largely ignore that line.
Comments, critiques, criticisms, perhaps anyone else building engines that have their own pieces from a similar era (of any size, design, or purpose)? I'd love to see what others are doing at the early end of the industry since most are using only the latest and greatest tech in their showcases here it seems.