You can always do things to “hide” your mods. You can find a 261 they do pop up for sale here once in a while. If you install it it will look close to a 216. Also the transmission, you can get a sm420 to swap in and with the right bellhousing keep your stomp starter and it will bolt up to the 261. There is a mod you have to do that’s on this forum to be able to bolt your clutch pedal up to the 420. But the 420 will look very similar to your current trans but with synchronizes it will shift much better and 99% wouldn’t even know.... he’ll you’d have to crawl under the truck and know exactly what you’re looking for to tell the difference. If you want to keep the original look inside, keep the original seat but install seatbelts. There are many ways you can fool the 99% and make upgrades that “look” original.