I ain’t trying to pick on you, but your love for the 273 clouds your judgement. It’s a great motor, but not the best option for this situation.
The car is a total rust bucket with years of back fees at the DMV. $1000 for a clapped out 273 and cable shifted 904 just isn’t worth it in our area. Junk yards full of 318’s with a guarantee(you can buy an additional 12 month warranty too) and marketplace/Craigslist is full of v8 904’s for cheap or free.
If it don’t make dollars, it don’t make sense.