Want to fix up my 1985 D150 for my Daughter!

My son had an 84 D100 regular cab.
I built up a 2.74 wide ratio trans, installed it and a spare 3.23SG chunk I had, for a starter gear of 8.85. And a 2800TC
The engine is stock 1973 low-c teener with a small-port CI 4bbl intake and TQ, No headers, but dual exhaust.Stock cam but extra spring pressure to pull 5400rpm.
She runs 275/60-15 tires (28s) and goes like stink,hitting 50 at the top of first gear. Second not so much. And cruises at 65~2500calculated no slip/2600 observed.
In our case, the wide ratio trans was worth it because we had no preconceived notion of trying to be quick in second gear, so the 2.74 x3.23= 8.85 starter gear is nearly the same as 2.45x3.55=8.70; but carries the ~12% less hiway rpms, And he traveled a lotta hiway. That 5% fuel savings over the course of time provides some rent-money, living in the big city.
One summer tho, he borrowed my 3.55s, which he spotted just sitting in a pail while my hotrod was running I think 4.30s. you shoulda heard the stories !!
This was my sons first vehicle and he drove it for close to 10 years . As you may think, the body is now shot,lol, with only the roof panel still being straight.
After he wore the body out, he traded it to me for a 95 Sunfire that was my winter-beater. IDK what to do with the D,now.
_______________
With the 268 cam,and somewhere around 9.5 Scr, you are gonna need some TM,Torque Multiplication, or at least the 2800TC. The 2.74 low gear trans is ~12% better, or equal to better than one rear gear size advantage; or about 5% better fuel mileage, in steady state, if you opt for 3.23s instead of 3.55s.
Happy Hotrodding