UTG engine build "callout"
Hack out the air cleaner for better flow into a screwed around with carb that flows more as well into a modified (AKA - prepped& ported) intake and cylinder head. Mill for more compression.
The pistons would be shaved and lightened. Rods would be lightened & smoothed. If I had to stay with the stock stroke, fine, but “up” stroking the crank would be my personal touch if legal. But otherwise, work the counter weights thinner & lighten the crank, cut down on the bearing width.
Fabricate my own windage tray and crank scraper. Cut and re-weld the oil pan and pick up deeper. Shim the oil pump relief spring. Port the exhaust manifolds.
Coat the inside of the block for quicker oil return and coat ever surface of every part with oil shedding material. Coat the piston tops & head chambers.
That’s were I’d start.